Browser enforces safe limit on messages sending messages and is limited to 64Kb as per here and is exiting with an error usually (1009 twilio's case )
From testing from browser console do
echoTest() for checking the connectivity
receiveJunk() for receiving huge messages (1.6mb) from server
send(junk) for sending huge message from client terminates the websocket...
Note: uncomment
maxReceivedMessageSize: 17486050,
maxReceivedFrameSize: 17486050,
these lines in server.js and run send(junk)