structured compute basics (#714)

this change adds the `zencompute` component, which can be used to distribute work dispatched from UE using the DDB (Derived Data Build) APIs via zenserver

this change also adds a distinct zenserver compute mode (`zenserver compute`) which is intended to be used for leaf compute nodes

to exercise the compute functionality without directly involving UE, a `zen exec` subcommand is also added, which can be used to feed replays through the system

all new functionality is considered *experimental* and disabled by default at this time, behind the `zencompute` option in xmake config

2 files changed, 40 insertions, 0 deletions

diff --git a/src/zennet/include/zennet/beacon.h b/src/zennet/include/zennet/beacon.h
new file mode 100644
index 000000000..a8d4805cb
--- /dev/null
+++ b/src/zennet/include/zennet/beacon.h
@@ -0,0 +1,38 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#pragma once
+
+#include <zennet/zennet.h>
+
+#include <zencore/uid.h>
+
+#include <filesystem>
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace zen {
+
+class CbObject;
+
+/** File-system based peer discovery
+
+	Intended to be used with an SMB file share as the root.
+  */
+
+class FsBeacon
+{
+public:
+	FsBeacon(std::filesystem::path ShareRoot);
+	~FsBeacon();
+
+	void AddGroup(std::string_view GroupId, CbObject Metadata);
+	void ScanGroup(std::string_view GroupId, std::vector<Oid>& OutSessions);
+	void ReadMetadata(std::string_view GroupId, const std::vector<Oid>& InSessions, std::vector<CbObject>& OutMetadata);
+
+private:
+	struct Impl;
+	std::unique_ptr<Impl> m_Impl;
+};
+
+}  // namespace zen
diff --git a/src/zennet/include/zennet/statsdclient.h b/src/zennet/include/zennet/statsdclient.h
index c378e49ce..7688c132c 100644
--- a/src/zennet/include/zennet/statsdclient.h
+++ b/src/zennet/include/zennet/statsdclient.h
@@ -8,6 +8,8 @@
 #include <memory>
 #include <string_view>
 
+#undef SendMessage
+
 namespace zen {
 
 class StatsTransportBase