The remote endpoint was in state [TEXT_FULL_WRITING] which is an invalid state for called method

Issue

• WsRemoteEndpointAsync.sendText does not appear to be thread safe since w are seeing an exception like the following when it is called in multiple threads at once:

2016-04-19 08:30:11,892 ERROR [stderr] (pool-10-thread-7195) Exception in thread "pool-10-thread-7195" java.lang.IllegalStateException: JBWEB008529: The remote endpoint was in state [TEXT_FULL_WRITING] which is an invalid state for called method
2016-04-19 08:30:11,892 ERROR [stderr] (pool-10-thread-7195)    at org.apache.tomcat.websocket.WsRemoteEndpointImplBase$StateMachine.checkState(WsRemoteEndpointImplBase.java:1137)
2016-04-19 08:30:11,892 ERROR [stderr] (pool-10-thread-7195)    at org.apache.tomcat.websocket.WsRemoteEndpointImplBase$StateMachine.textStart(WsRemoteEndpointImplBase.java:1100)
2016-04-19 08:30:11,892 ERROR [stderr] (pool-10-thread-7195)    at org.apache.tomcat.websocket.WsRemoteEndpointImplBase.sendStringByCompletion(WsRemoteEndpointImplBase.java:200)
2016-04-19 08:30:11,893 ERROR [stderr] (pool-10-thread-7195)    at org.apache.tomcat.websocket.WsRemoteEndpointImplBase.sendStringByFuture(WsRemoteEndpointImplBase.java:188)
2016-04-19 08:30:11,893 ERROR [stderr] (pool-10-thread-7195)    at org.apache.tomcat.websocket.WsRemoteEndpointAsync.sendText(WsRemoteEndpointAsync.java:53)