Debugger: Use fragments for long chunks.

Gets it on the wire faster.  More importantly, this allows us to usually
avoid rampant memory allocation even for large responses.

Core/Debugger/WebSocket/WebSocketUtils.cpp

@@ -32,12 +32,21 @@ JsonWriter &DebuggerRequest::Respond() {
 void DebuggerRequest::Finish() {
 	if (responseBegun_ && !responseSent_) {
 		writer_.end();
-		ws->Send(writer_.str());
+		if (responsePartial_)
+			ws->AddFragment(true, writer_.str());
+		else
+			ws->Send(writer_.str());
 		responseBegun_ = false;
 		responseSent_ = true;
+		responsePartial_ = false;
 	}
 }
 
+void DebuggerRequest::Flush() {
+	ws->AddFragment(false, writer_.flush());
+	responsePartial_ = true;
+}
+
 static bool U32FromString(const char *str, uint32_t *out, bool allowFloat) {
 	if (TryParse(str, out))
 		return true;