public BufferedMutatorParams setWriteBufferPeriodicFlushTimeoutMs(long timeoutMs) {
    this.writeBufferPeriodicFlushTimeoutMs = timeoutMs;
    return this;
  }
Set the max timeout before the buffer is automatically flushed.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/BufferedMutatorParams.java