private void releaseLock(long procId) throws ServiceException {
    masterRpcService.lockHeartbeat(null,
      LockHeartbeatRequest.newBuilder().setProcId(procId).setKeepAlive(false).build());
  }
Returns immediately if the lock is acquired.
@throws TimeoutException if lock couldn't be acquired.
hbase-server/src/test/java/org/apache/hadoop/hbase/master/locking/TestLockProcedure.java