synchronized void respondWithTryLockFailed(Object keyIfFailed) {
      response.responseCode = DLockResponseMessage.TRY_LOCK_FAILED;
      response.keyIfFailed = keyIfFailed;
      sendResponse();
    }
Callers must be synchronized on this
geode-core/src/main/java/org/apache/geode/distributed/internal/locks/DLockRequestProcessor.java