use spdlog for logging in ws + unittest + remove un-needed mutex

third_party/spdlog/include/spdlog/sinks/ostream_sink.h

@@ -0,0 +1,57 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#ifndef SPDLOG_H
+#include "spdlog/spdlog.h"
+#endif
+
+#include "spdlog/details/null_mutex.h"
+#include "spdlog/sinks/base_sink.h"
+
+#include <mutex>
+#include <ostream>
+
+namespace spdlog {
+namespace sinks {
+template<typename Mutex>
+class ostream_sink final : public base_sink<Mutex>
+{
+public:
+    explicit ostream_sink(std::ostream &os, bool force_flush = false)
+        : ostream_(os)
+        , force_flush_(force_flush)
+    {
+    }
+    ostream_sink(const ostream_sink &) = delete;
+    ostream_sink &operator=(const ostream_sink &) = delete;
+
+protected:
+    void sink_it_(const details::log_msg &msg) override
+    {
+        fmt::memory_buffer formatted;
+        sink::formatter_->format(msg, formatted);
+        ostream_.write(formatted.data(), static_cast<std::streamsize>(formatted.size()));
+        if (force_flush_)
+        {
+            ostream_.flush();
+        }
+    }
+
+    void flush_() override
+    {
+        ostream_.flush();
+    }
+
+    std::ostream &ostream_;
+    bool force_flush_;
+};
+
+using ostream_sink_mt = ostream_sink<std::mutex>;
+using ostream_sink_st = ostream_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog