Allow websocket handlers to reply more than one frame

Instead of returning {text, Data}, you can now return
[{text, Data}, {text, Data2}, ...].

test/ws_send_many_handler.erl

@@ -0,0 +1,31 @@
+%% Feel free to use, reuse and abuse the code in this file.
+
+-module(ws_send_many_handler).
+-behaviour(cowboy_websocket_handler).
+
+-export([init/3]).
+-export([websocket_init/3]).
+-export([websocket_handle/3]).
+-export([websocket_info/3]).
+-export([websocket_terminate/3]).
+
+init(_Any, _Req, _Opts) ->
+	{upgrade, protocol, cowboy_websocket}.
+
+websocket_init(_TransportName, Req, _Opts) ->
+	Req2 = cowboy_req:compact(Req),
+	erlang:send_after(10, self(), send_many),
+	{ok, Req2, undefined}.
+
+websocket_handle(_Frame, Req, State) ->
+	{ok, Req, State}.
+
+websocket_info(send_many, Req, State) ->
+	{reply, [
+		{text, <<"one">>},
+		{text, <<"two">>},
+		{text, <<"seven!">>}
+	], Req, State}.
+
+websocket_terminate(_Reason, _Req, _State) ->
+	ok.