docs: public NettyServerBuilder keepAliveTime(long keepAliveTime, TimeUnit timeUnit) {
      checkArgument(keepAliveTime > 0L, "keepalive time must be positive");
      keepAliveTimeInNanos = timeUnit.toNanos(keepAliveTime);
      keepAliveTimeInNanos = KeepAliveManager.clampKeepAliveTimeInNanos(keepAliveTimeInNanos);
      if (keepAliveTimeInNanos >= AS_LARGE_AS_INFINITE) {
        // Bump keepalive time to infinite. This disables keep alive.
        keepAliveTimeInNanos = SERVER_KEEPALIVE_TIME_NANOS_DISABLED;
      }
      if (keepAliveTimeInNanos < MIN_KEEPALIVE_TIME_NANO) {
        // Bump keepalive time.
        keepAliveTimeInNanos = MIN_KEEPALIVE_TIME_NANO;
      }
      return this;
    }