refactor(streamer): adopt proxy backends and typed statuses

include/cvmmap_streamer/protocol/rtmp_output.hpp

@@ -0,0 +1,30 @@
+#pragma once
+
+#include "cvmmap_streamer/config/runtime_config.hpp"
+#include "cvmmap_streamer/core/status.hpp"
+#include "cvmmap_streamer/encode/encoded_access_unit.hpp"
+
+#include <string_view>
+
+#include <proxy/proxy.h>
+
+namespace cvmmap_streamer::protocol {
+
+PRO_DEF_MEM_DISPATCH(MemBackendName, backend_name);
+PRO_DEF_MEM_DISPATCH(MemPublishAccessUnit, publish_access_unit);
+PRO_DEF_MEM_DISPATCH(MemLogMetrics, log_metrics);
+
+struct RtmpOutputFacade : pro::facade_builder
+	::add_convention<MemBackendName, std::string_view() const>
+	::add_convention<MemPublishAccessUnit, Status(const encode::EncodedAccessUnit &)>
+	::add_convention<MemLogMetrics, void() const>
+	::build {};
+
+using RtmpOutput = pro::proxy<RtmpOutputFacade>;
+
+[[nodiscard]]
+Result<RtmpOutput> make_rtmp_output(
+	const RuntimeConfig &config,
+	const encode::EncodedStreamInfo &stream_info);
+
+}