* add a new IToolForm update mechanism which has extensible update points (so a tool can both pre- and post- update)

* make trace logging "core-pushes" model, to a sink installed by the frontend. This sink can go straight to the disk without wasting memory if that's what the Trace Logger tool has selected; or the Trace Logger will buffer it if it needs to.  Formerly, we had a "core-pushes-to-buffer" and "client-pulls-once-per-frame" which necessarily caused huge buffers no matter what was going on.

BizHawk.Client.Common/tools/Interfaces/IToolForm.cs

@@ -1,11 +1,35 @@
 namespace BizHawk.Client.EmuHawk
 {
+	public enum ToolFormUpdateType
+	{
+		//reserved
+		Legacy, LegacyFast,
+
+		//reserved concept: we can run other events through here (should probably rename then)
+		Reset,
+
+		/// <summary>
+		/// Called before a frame emulates
+		/// </summary>
+		PreFrame,
+
+		/// <summary>
+		/// Called after a frame emulates
+		/// </summary>
+		PostFrame
+	}
+
 	public interface IToolForm
 	{
 		/// <summary>
 		/// Will be called by the client anytime an Update needs to occur, such as after an emulated frame, a loadstate, or a related dialog has made a relevant change
 		/// </summary>
-		void UpdateValues();
+		void UpdateValues();
+
+		/// <summary>
+		/// A new extensible update method
+		/// </summary>
+		void NewUpdate(ToolFormUpdateType type);
 
 		/// <summary>
 		/// Will be called by the client when performance is critical,
@@ -32,6 +56,7 @@
 		/// Indicates whether the tool should be updated before a frame loop or after.
 		/// In general, tools that draw graphics from the core should update before the loop,
 		/// Information tools such as those that display core ram values should be after.
+		/// AWESOME! no separate preupdate and postupdate hooks. seriously?
 		/// </summary>
 		bool UpdateBefore { get; }
 

BizHawk.Client.EmuHawk/CoreFeatureAnalysis.cs

@@ -129,6 +129,8 @@ namespace BizHawk.Client.EmuHawk
 			Close();
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		private TreeNode CreateCoreTree(CoreInfo ci)
 		{
 			var ret = new TreeNode

BizHawk.Client.EmuHawk/config/NES/NESSoundConfig.cs

@@ -21,6 +21,8 @@ namespace BizHawk.Client.EmuHawk
 		{
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void FastUpdate()
 		{
 		}

BizHawk.Client.EmuHawk/tools/AutoHawk.cs

@@ -40,6 +40,8 @@ namespace BizHawk.Client.EmuHawk
 
 		#region IToolForm Implementation
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			// TODO: per frame stuff goes here

BizHawk.Client.EmuHawk/tools/BasicBot/BasicBot.cs

@@ -371,6 +371,8 @@ namespace BizHawk.Client.EmuHawk
 
 		public bool UpdateBefore { get { return true; } }
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			Update(fast: false);

BizHawk.Client.EmuHawk/tools/CDL.cs

@@ -63,7 +63,9 @@ namespace BizHawk.Client.EmuHawk
 			InitializeComponent();
 
 			tsbViewStyle.SelectedIndex = 0;
-		}
+		}
+
+		public void NewUpdate(ToolFormUpdateType type) { }
 
 		public void UpdateValues()
 		{

BizHawk.Client.EmuHawk/tools/Cheats/Cheats.cs

@@ -58,6 +58,8 @@ namespace BizHawk.Client.EmuHawk
 
 		public bool UpdateBefore { get { return false; } }
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			// Do nothing

BizHawk.Client.EmuHawk/tools/Debugger/BreakpointControl.cs

@@ -86,6 +86,8 @@ namespace BizHawk.Client.EmuHawk.tools.Debugger
 			ParentDebugger.DisableCancelSeekBtn();
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			if (Enabled)

BizHawk.Client.EmuHawk/tools/Debugger/GenericDebugger.IToolForm.cs

@@ -134,6 +134,8 @@ namespace BizHawk.Client.EmuHawk
 
 		#endregion
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			// Nothing to do

BizHawk.Client.EmuHawk/tools/Debugger/RegisterBoxControl.cs

@@ -33,6 +33,8 @@ namespace BizHawk.Client.EmuHawk
 
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			if (this.Enabled)

BizHawk.Client.EmuHawk/tools/GB/GBGPUView.cs

@@ -533,6 +533,8 @@ namespace BizHawk.Client.EmuHawk
 		/// </summary>
 		int cbscanline_emu = -4; // force refresh
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		/// <summary>
 		/// put me in ToolsBefore
 		/// </summary>

BizHawk.Client.EmuHawk/tools/GB/GBGameGenie.cs

@@ -33,6 +33,8 @@ namespace BizHawk.Client.EmuHawk
 				Close();
 			}
 		}
+
+		public void NewUpdate(ToolFormUpdateType type) { }
 		
 		public void UpdateValues()
 		{

BizHawk.Client.EmuHawk/tools/GBA/GBAGPUView.cs

@@ -693,6 +693,8 @@ namespace BizHawk.Client.EmuHawk
 			UpdateValues();
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		/// <summary>belongs in ToolsBefore</summary>
 		public void UpdateValues()
 		{

BizHawk.Client.EmuHawk/tools/GameShark.cs

@@ -154,7 +154,9 @@ namespace BizHawk.Client.EmuHawk
 		public void Restart()
 		{
 
-		}
+		}
+
+		public void NewUpdate(ToolFormUpdateType type) { }
 
 		public void UpdateValues()
 		{

BizHawk.Client.EmuHawk/tools/Genesis/GenGameGenie.cs

@@ -85,6 +85,8 @@ namespace BizHawk.Client.EmuHawk
 			}
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			if (Emulator.SystemId != "GEN")

BizHawk.Client.EmuHawk/tools/Genesis/VDPViewer.cs

@@ -119,6 +119,7 @@ namespace BizHawk.Client.EmuHawk
 			bmpViewTiles.Refresh();
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
 
 		public void UpdateValues()
 		{

BizHawk.Client.EmuHawk/tools/HexEditor/HexEditor.cs

@@ -146,6 +146,8 @@ namespace BizHawk.Client.EmuHawk
 			return true;
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			AddressesLabel.Text = GenerateMemoryViewString(true);

BizHawk.Client.EmuHawk/tools/HexEditor/NewHexEditor.cs

@@ -41,7 +41,9 @@ namespace BizHawk.Client.EmuHawk
 
 		#endregion
 
-		#region IToolForm implementation
+		#region IToolForm implementation
+
+		public void NewUpdate(ToolFormUpdateType type) { }
 
 		public void UpdateValues()
 		{

BizHawk.Client.EmuHawk/tools/Lua/LuaConsole.cs

@@ -94,6 +94,8 @@ namespace BizHawk.Client.EmuHawk
 			get { return SelectedItems.Where(x => !x.IsSeparator); }
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			// Do nothing

BizHawk.Client.EmuHawk/tools/Lua/LuaRegisteredFunctionsList.cs

@@ -13,6 +13,8 @@ namespace BizHawk.Client.EmuHawk
 			InitializeComponent();
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			if (GlobalWin.Tools.LuaConsole.LuaImp.RegisteredFunctions.Any())

BizHawk.Client.EmuHawk/tools/Macros/MacroInput.cs

@@ -80,6 +80,8 @@ namespace BizHawk.Client.EmuHawk
 			MacroInputTool_Load(null, null);
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		// These do absolutely nothing.
 		public void UpdateValues()
 		{

BizHawk.Client.EmuHawk/tools/MultiDiskBundler/MultiDiskBundler.cs

@@ -57,6 +57,8 @@ namespace BizHawk.Client.EmuHawk
 
 		#region IToolForm
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 

BizHawk.Client.EmuHawk/tools/MultiDiskBundler/MultiDiskFileSelector.cs

@@ -100,6 +100,8 @@ namespace BizHawk.Client.EmuHawk
 			UpdateValues();
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			UseCurrentRomButton.Enabled = Global.Emulator != null // For the designer

BizHawk.Client.EmuHawk/tools/NES/BarcodeEntry.cs

@@ -25,6 +25,8 @@ namespace BizHawk.Client.EmuHawk
 
 		#region IToolForm
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 		}

BizHawk.Client.EmuHawk/tools/NES/NESGameGenie.cs

@@ -55,6 +55,8 @@ namespace BizHawk.Client.EmuHawk
 			}
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			if (Emulator.SystemId != "NES")

BizHawk.Client.EmuHawk/tools/NES/NESMusicRipper.cs

@@ -33,6 +33,8 @@ namespace BizHawk.Client.EmuHawk
 		{
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 		}

BizHawk.Client.EmuHawk/tools/NES/NESNameTableViewer.cs

@@ -47,6 +47,8 @@ namespace BizHawk.Client.EmuHawk
 			Generate(true);
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			_ppu.InstallCallback1(() => Generate(), scanline);

BizHawk.Client.EmuHawk/tools/NES/NESPPU.cs

@@ -63,6 +63,7 @@ namespace BizHawk.Client.EmuHawk
 		public bool AskSaveChanges() { return true; }
 		public bool UpdateBefore { get { return true; } }
 
+		public void NewUpdate(ToolFormUpdateType type) { }
 		public void UpdateValues()
 		{
 			_ppu.InstallCallback2(() => Generate(), scanline);

BizHawk.Client.EmuHawk/tools/PCE/PCEBGViewer.cs

@@ -94,6 +94,8 @@ namespace BizHawk.Client.EmuHawk
 			// Nothing to do
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			Generate();

BizHawk.Client.EmuHawk/tools/PCE/PCESoundDebugger.cs

@@ -42,6 +42,8 @@ namespace BizHawk.Client.EmuHawk
 			base.OnShown(e);
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			foreach (var entry in PSGEntries)

BizHawk.Client.EmuHawk/tools/PCE/PCETileViewer.cs

@@ -32,6 +32,8 @@ namespace BizHawk.Client.EmuHawk
 
 		#region IToolForm
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			DrawBacks();

BizHawk.Client.EmuHawk/tools/SMS/VDPViewer.cs

@@ -139,6 +139,8 @@ namespace BizHawk.Client.EmuHawk
 			bmpViewPalette.Refresh();
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			unsafe

BizHawk.Client.EmuHawk/tools/SNES/SNESGameGenie.cs

@@ -63,6 +63,8 @@ namespace BizHawk.Client.EmuHawk
 			// Do nothing
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			// Do nothing

BizHawk.Client.EmuHawk/tools/SNES/SNESGraphicsDebugger.cs

@@ -133,6 +133,8 @@ namespace BizHawk.Client.EmuHawk
 			else return string.Format("@{0} ({1}K)", address.ToHexString(4), address / 1024);
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			SyncCore();

BizHawk.Client.EmuHawk/tools/TAStudio/TAStudio.IToolForm.cs

@@ -22,6 +22,8 @@ namespace BizHawk.Client.EmuHawk
 
 		public bool UpdateBefore { get { return false; } }
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		private int lastRefresh = 0;
 		public void UpdateValues()
 		{

BizHawk.Client.EmuHawk/tools/TI83/TI83KeyPad.cs

@@ -41,6 +41,8 @@ namespace BizHawk.Client.EmuHawk
 		public bool AskSaveChanges() { return true; }
 		public bool UpdateBefore { get { return false; } }
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			// Do nothing

BizHawk.Client.EmuHawk/tools/ToolBox.cs

@@ -33,6 +33,8 @@ namespace BizHawk.Client.EmuHawk
 			);
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public bool AskSaveChanges() { return true;  }
 		public bool UpdateBefore { get { return false; } }
 		public void UpdateValues() { }

BizHawk.Client.EmuHawk/tools/ToolManager.cs

@@ -405,6 +405,8 @@ namespace BizHawk.Client.EmuHawk
 					tool.UpdateValues();
 				}
 			}
+			foreach (var tool in _tools)
+				tool.NewUpdate(ToolFormUpdateType.PreFrame);
 		}
 
 		public void UpdateAfter()
@@ -418,6 +420,9 @@ namespace BizHawk.Client.EmuHawk
 					tool.UpdateValues();
 				}
 			}
+
+			foreach (var tool in _tools)
+				tool.NewUpdate(ToolFormUpdateType.PostFrame);
 		}
 
 		/// <summary>

BizHawk.Client.EmuHawk/tools/TraceLogger.cs

@@ -33,9 +33,10 @@ namespace BizHawk.Client.EmuHawk
 			set { this.Registers.Width = value; }
 		}
 
-		private readonly List<TraceInfo> _instructions = new List<TraceInfo>();
+		private List<TraceInfo> _instructions = new List<TraceInfo>();
 		
 		private FileInfo _logFile;
+		private StreamWriter _streamWriter;
 
 		public TraceLogger()
 		{
@@ -61,7 +62,7 @@ namespace BizHawk.Client.EmuHawk
 
 		private void SaveConfigSettings()
 		{
-			Tracer.Enabled = LoggingEnabled.Checked;
+			//Tracer.Enabled = LoggingEnabled.Checked;
 		}
 
 		private void TraceView_QueryItemText(int index, int column, out string text)
@@ -77,7 +78,6 @@ namespace BizHawk.Client.EmuHawk
 					case 1:
 						text = _instructions[index].RegisterInfo;
 						break;
-
 				}
 			}
 		}
@@ -86,35 +86,79 @@ namespace BizHawk.Client.EmuHawk
 		{
 			ClearList();
 			OpenLogFile.Enabled = false;
-			Tracer.Enabled = LoggingEnabled.Checked = false;
+			//Tracer.Enabled = LoggingEnabled.Checked = false;
 			SetTracerBoxTitle();
 		}
 
-		public void UpdateValues()
+		class CallbackSink : ITraceSink
 		{
-			_instructions.AddRange(Tracer.TakeContents());
-
-			if (ToWindowRadio.Checked)
+			public void Put(TraceInfo info)
 			{
-				TraceView.BlazingFast = !GlobalWin.MainForm.EmulatorPaused;
-				LogToWindow();
+				putter(info);
 			}
-			else
+
+			public Action<TraceInfo> putter;
+		}
+
+		public void UpdateValues() { }
+
+		public void NewUpdate(ToolFormUpdateType type)
+		{
+			if (type == ToolFormUpdateType.PostFrame)
 			{
-				DumpToDisk(_logFile);
-				_instructions.Clear();
+				if (ToWindowRadio.Checked)
+					TraceView.VirtualListSize = _instructions.Count;
+				else
+				{
+					_streamWriter.Close();
+					_streamWriter = null;
+				}
+			}
+
+			if (type == ToolFormUpdateType.PreFrame)
+			{
+				if (LoggingEnabled.Checked)
+				{
+					//connect tracer to sink for next frame
+					if (ToWindowRadio.Checked)
+					{
+						//update listview with most recentr results
+						TraceView.BlazingFast = !GlobalWin.MainForm.EmulatorPaused;
+
+						Tracer.Sink = new CallbackSink()
+						{
+							putter = (info) =>
+							{
+								if (_instructions.Count >= MaxLines) { }
+								else _instructions.Add(info);
+							}
+						};
+						_instructions.Clear();
+					}
+					else
+					{
+						_streamWriter = new StreamWriter(_logFile.FullName, append: true);
+						Tracer.Sink = new CallbackSink {
+							putter = (info) =>
+							{
+								//no padding supported. core should be doing this anyway.
+								_streamWriter.WriteLine("{0}    {1}", info.Disassembly, info.RegisterInfo);
+							}
+						};
+					}
+				}
+				else Tracer.Sink = null;
 			}
 		}
 
 		public void FastUpdate()
 		{
-			_instructions.AddRange(Tracer.TakeContents());
 		}
 
 		public void Restart()
 		{
 			ClearList();
-			Tracer.Enabled = LoggingEnabled.Checked = false;
+			//Tracer.Enabled = LoggingEnabled.Checked = false;
 			SetTracerBoxTitle();
 		}
 
@@ -290,7 +334,7 @@ namespace BizHawk.Client.EmuHawk
 
 		private void LoggingEnabled_CheckedChanged(object sender, EventArgs e)
 		{
-			Tracer.Enabled = LoggingEnabled.Checked;
+			//Tracer.Enabled = LoggingEnabled.Checked;
 			SetTracerBoxTitle();
 
 			if (LoggingEnabled.Checked && _logFile != null)

BizHawk.Client.EmuHawk/tools/VirtualPads/VirtualpadsTool.cs

@@ -168,6 +168,8 @@ namespace BizHawk.Client.EmuHawk
 			CreatePads();
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			if (!IsHandleCreated || IsDisposed)

BizHawk.Client.EmuHawk/tools/Watch/RamSearch.cs

@@ -261,6 +261,8 @@ namespace BizHawk.Client.EmuHawk
 			SetTotal();
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		/// <summary>
 		/// This should only be called when the values of the list need an update such as after a poke or emulation occured
 		/// </summary>

BizHawk.Client.EmuHawk/tools/Watch/RamWatch.cs

@@ -229,6 +229,8 @@ namespace BizHawk.Client.EmuHawk
 			}
 		}
 
+		public void NewUpdate(ToolFormUpdateType type) { }
+
 		public void UpdateValues()
 		{
 			if (_paused)

BizHawk.Emulation.Common/Base Implementations/CallbackBasedTraceBuffer.cs

@@ -36,51 +36,35 @@ namespace BizHawk.Emulation.Common
 
 		protected readonly List<TraceInfo> Buffer = new List<TraceInfo>();
 
-		private bool _enabled;
-
-		public abstract void TraceFromCallback();
-
-		public bool Enabled
-		{
-			get
-			{
-				return _enabled;
-			}
-
-			set
-			{
-				_enabled = value;
-				DebuggableCore.MemoryCallbacks.Remove(TraceFromCallback);
-
-				if (_enabled)
-				{
-					DebuggableCore.MemoryCallbacks.Add(new TracingMemoryCallback(TraceFromCallback));
-				}
-			}
+		public abstract void TraceFromCallback();
+
+		public ITraceSink _sink;
+
+		public bool Enabled { get { return Sink != null; } }
+
+		public void Put(TraceInfo info) { Sink.Put(info); }
+
+		public ITraceSink Sink
+		{
+			get
+			{
+				return _sink;
+			}
+			set
+			{
+				_sink = value;
+				DebuggableCore.MemoryCallbacks.Remove(TraceFromCallback);
+
+				if (_sink != null)
+				{
+					DebuggableCore.MemoryCallbacks.Add(new TracingMemoryCallback(TraceFromCallback));
+				}
+			}
 		}
 
+
 		public string Header { get; set; }
 
-		public IEnumerable<TraceInfo> Contents
-		{
-			get { return Buffer; }
-		}
-
-		public IEnumerable<TraceInfo> TakeContents()
-		{
-			var contents = Buffer.ToList();
-			Buffer.Clear();
-			return contents;
-		}
-
-		public void Put(TraceInfo content)
-		{
-			if (Enabled)
-			{
-				Buffer.Add(content);
-			}
-		}
-
 		public class TracingMemoryCallback : IMemoryCallback
 		{
 			public TracingMemoryCallback(Action callback)

BizHawk.Emulation.Common/Base Implementations/TraceBuffer.cs

@@ -1,39 +1,23 @@
 using System.Collections.Generic;
 using System.Linq;
 
+//garbage
+
 namespace BizHawk.Emulation.Common
 {
 	public class TraceBuffer : ITraceable
 	{
-		private readonly List<TraceInfo> Buffer = new List<TraceInfo>();
-
 		public TraceBuffer()
 		{
 			Header = "Instructions";
 		}
 
-		public IEnumerable<TraceInfo> TakeContents()
-		{
-			var contents = Buffer.ToList();
-			Buffer.Clear();
-			return contents;
-		}
-
-		public IEnumerable<TraceInfo> Contents
-		{
-			get { return Buffer; }
-		}
-
-		public void Put(TraceInfo content)
-		{
-			if (Enabled)
-			{
-				Buffer.Add(content);
-			}
-		}
-
-		public bool Enabled { get; set; }
-
 		public string Header { get; set; }
+
+		public ITraceSink Sink { get; set; }
+
+		public bool Enabled { get { return Sink != null; } }
+
+		public void Put(TraceInfo info) { Sink.Put(info); }
 	}
 }

BizHawk.Emulation.Common/Interfaces/Services/ITraceable.cs

@@ -2,13 +2,18 @@
 
 namespace BizHawk.Emulation.Common
 {
+	public interface ITraceSink
+	{
+		void Put(TraceInfo info);
+	}
+
 	/// <summary>
 	/// This service allows the core to dump a cpu trace to the client
 	/// If available the Trace Logger tool will be available on the client
 	/// </summary>
 	public interface ITraceable : IEmulatorService
 	{
-		bool Enabled { get; set; }
+		//bool Enabled { get; set; }
 
 		/// <summary>
 		/// The header that would be used by a trace logger
@@ -18,14 +23,30 @@ namespace BizHawk.Emulation.Common
 		/// <summary>
 		/// The current log of cpu instructions
 		/// </summary>
-		IEnumerable<TraceInfo> Contents { get; }
+		//IEnumerable<TraceInfo> Contents { get; }
 
 		/// <summary>
 		/// Takes the current log of cpu instructions, when doing so, it will clear the contents from the buffer
 		/// </summary>
-		IEnumerable<TraceInfo> TakeContents();
+		//IEnumerable<TraceInfo> TakeContents();
 
-		void Put(TraceInfo content);
+		//void Put(TraceInfo content);
+
+		//that's right, we can only have one sink.
+		//a sink can route to two other sinks if it has to, though
+		ITraceSink Sink { get; set; }
+
+		/// <summary>
+		/// This is defined as equivalent to Sink != null
+		/// It's put here because it's such a common operation to check whether it's enabled, and it's not nice to write Sink != null all over
+		/// </summary>
+		bool Enabled { get; }
+
+		/// <summary>
+		/// This is defined as equivalent to Sink.Put
+		/// TBD: could it be defined as equivalent to if(Enabled) Sink.Put()? Probably not, that's just a small amount of wasted work
+		/// </summary>
+		void Put(TraceInfo info);
 	}
 
 	public class TraceInfo