[EventPipe] Adding an IPC server to handle out of process communication. (#23106)

This is the first commit to enable a "diagnostic port" using IPC (Named Pipe on Windows and Unix Domain Socket on other platforms). This change currently enable EventPipe to be enabled/disabled without the use of a file drop.
- Split the DiagnosticsIpc into (DiagnosticsIpc/IpcStream)
  - DiagnosticsIpc (IPC listener) is meant to be used by the Diagnostic server.
  - IpcStream (IPC channel) is meant to be use to communicate with the connected client.
- Change the FastSerializer dependency from `CFileStream` to `StreamWriter`
  This abstraction is meant decouple the writing of objects in order to extend its usability.
  The main objective is to reuse FastSerializer to stream data through the open IPC channel.
- Moved the EventPipeSessionProvider* classes to their own file.
- Added a more streamlined parsing achievable by defining a simpler binary protocol (by noahfalk).
  1. Only one allocation is needed for the EventPipeProviderConfiguration array, no allocations or copies are needed for strings because we can refer to them directly out of the incoming command buffer
  2. No change to the EventPipe API for enable is required. EventPipeProviderConfiguration retains its current behavior of not deleting the string pointers it holds.
  3. No leaks happen because the command buffer owns the string memory and ensures that it stays alive for the duration of the Enable() call.

1 files changed, 58 insertions, 0 deletions

diff --git a/src/vm/diagnosticserver.h b/src/vm/diagnosticserver.h
new file mode 100644
index 0000000000..95399a2ef8
--- /dev/null
+++ b/src/vm/diagnosticserver.h
@@ -0,0 +1,58 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#ifndef __DIAGNOSTIC_SERVER_H__
+#define __DIAGNOSTIC_SERVER_H__
+
+#include <stdint.h>
+
+#ifdef FEATURE_PERFTRACING // This macro should change to something more generic than performance.
+
+//! TODO: Temp class.
+enum class DiagnosticMessageType : uint32_t
+{
+    ///////////////////////////////////////////////////////////////////////////
+    // Debug = 0
+
+    ///////////////////////////////////////////////////////////////////////////
+    // EventPipe
+    EnableEventPipe = 1024,
+    DisableEventPipe,
+
+    // TODO: Define what else is available on the out-of-proc interface?
+    // GetSessionInfo,
+    // CreateProvider,
+    // DefineEvent,
+    // GetProvider,
+    // DeleteProvider,
+    // EventActivityIdControl,
+    // WriteEvent,
+    // WriteEventData,
+    // GetNextEvent,
+
+    ///////////////////////////////////////////////////////////////////////////
+    // Profiler = 2048
+};
+
+//! TODO: Temp class.
+struct MessageHeader
+{
+    DiagnosticMessageType RequestType;
+    uint32_t Pid;
+};
+
+//! Defines an implementation of a IPC handler that dispatches messages to the runtime.
+class DiagnosticServer final
+{
+public:
+    //! Initialize the event pipe (Creates the EventPipe IPC server).
+    static bool Initialize();
+
+    //! Shutdown the event pipe.
+    static bool Shutdown();
+};
+
+#endif // FEATURE_PERFTRACING
+
+#endif // __DIAGNOSTIC_SERVER_H__