EventsHandler: Write serialized events directly into the stream

Instead of serializing the events into a JSON `String` and transforming
it into an Asio buffer, we can directly write the JSON into an Asio
stream using the new `JsonEncoder`.

Author: yhabteab

lib/remote/eventshandler.cpp

@@ -9,9 +9,9 @@
 #include "base/io-engine.hpp"
 #include "base/objectlock.hpp"
 #include "base/json.hpp"
-#include <boost/asio/buffer.hpp>
 #include <boost/asio/write.hpp>
 #include <boost/algorithm/string/replace.hpp>
+#include <boost/asio/streambuf.hpp>
 #include <map>
 #include <set>
 
@@ -110,20 +110,16 @@ bool EventsHandler::HandleRequest(
 	http::async_write(stream, response, yc);
 	stream.async_flush(yc);
 
-	asio::const_buffer newLine ("\n", 1);
+	auto adapter(std::make_shared<AsioStreamAdapter<AsioTlsStream>>(stream, yc));
+	JsonEncoder encoder(adapter);
 
 	for (;;) {
-		auto event (subscriber.GetInbox()->Shift(yc));
-
-		if (event) {
-			String body = JsonEncode(event);
-
-			boost::algorithm::replace_all(body, "\n", "");
-
-			asio::const_buffer payload (body.CStr(), body.GetLength());
-
-			asio::async_write(stream, payload, yc);
-			asio::async_write(stream, newLine, yc);
+		if (auto event(subscriber.GetInbox()->Shift(yc)); event) {
+			encoder.Encode(event);
+			// Put a newline at the end of each event to render them on a separate line.
+			adapter->async_put('\n');
+			// Since shifting the next event may cause the coroutine to yield, we need to flush the
+			// stream after each event to ensure that the client receives it immediately.
 			stream.async_flush(yc);
 		} else if (server.Disconnected()) {
 			return true;