sinks now parameterized by mutex T

include/c11log/sinks/isink.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "../details/log_msg.h"
+
+namespace c11log
+{
+namespace sinks
+{
+class isink
+{
+public:
+    virtual void log(const details::log_msg& msg) = 0;
+    virtual void enable(bool enabled) = 0;
+    virtual bool is_enabled() = 0;
+};
+}
+}
+