public long heartbeat( final char[] testReqId, final int testReqIdLength, final int msgSeqNo, final int sequenceIndex, final int lastMsgSeqNumProcessed) { final HeaderEncoder header = heartbeat.header(); setupHeader(header, msgSeqNo, lastMsgSeqNumProcessed); if (testReqId != null) { heartbeat.testReqID(testReqId, testReqIdLength); } else { heartbeat.resetTestReqID(); } final long result = heartbeat.encode(buffer, 0); return send(result, HeartbeatDecoder.MESSAGE_TYPE, sequenceIndex, heartbeat, msgSeqNo); }