code: public NettyServerBuilder keepAliveTimeout(long keepAliveTimeout, TimeUnit timeUnit) {
      checkArgument(keepAliveTimeout > 0L, "keepalive timeout must be positive");
      keepAliveTimeoutInNanos = timeUnit.toNanos(keepAliveTimeout);
      keepAliveTimeoutInNanos =
          KeepAliveManager.clampKeepAliveTimeoutInNanos(keepAliveTimeoutInNanos);
      if (keepAliveTimeoutInNanos < MIN_KEEPALIVE_TIMEOUT_NANO) {
        // Bump keepalive timeout.
        keepAliveTimeoutInNanos = MIN_KEEPALIVE_TIMEOUT_NANO;
      }
      return this;
    }
docs: Sets a custom keepalive timeout, the timeout for keepalive ping requests. An unreasonably small
  value might be increased.
  
  @since 1.3.0