code: void enableKeepAlive(boolean enable, long keepAliveTimeNanos,
        long keepAliveTimeoutNanos, boolean keepAliveWithoutCalls) {
      enableKeepAlive = enable;
      this.keepAliveTimeNanos = keepAliveTimeNanos;
      this.keepAliveTimeoutNanos = keepAliveTimeoutNanos;
      this.keepAliveWithoutCalls = keepAliveWithoutCalls;
    }
docs: Enable keepalive with custom delay and timeout.