Add a size function to the stream wrapper

src/common/serialization/clap/stream.h

@@ -45,6 +45,11 @@ class Stream {
      */
     Stream(const clap_istream_t& original);
 
+    /**
+     * The buffer's size in bytes, used for logging.
+     */
+    inline size_t size() const noexcept { return buffer_.size(); }
+
     /**
      * Get a `clap_ostream_t` for this buffer that the plugin can write to. This
      * is only valid as long as this object is not moved.