feat: add streams

include/sp/protocol/MessageBase.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <iosfwd>
+#include <sp/common/DataBuffer.h>
 
 namespace sp {
 
@@ -17,8 +18,8 @@ class MessageBase {
 
 	virtual void Dispatch(HandlerType& handler) const = 0;
 
-	virtual void Read(std::istream& a_Is) = 0;
-	virtual void Write(std::ostream& a_Os) const = 0;
+	virtual void Read(DataBuffer& a_Buffer) = 0;
+	virtual DataBuffer Write() const = 0;
 };
 
 }  // namespace sp