fromSink.writeByte(VERSION_5)
        fromSink.writeByte(REPLY_SUCCEEDED)
        fromSink.writeByte(0)
        fromSink.writeByte(ADDRESS_TYPE_IPV4)
        fromSink.write(localAddress)
        fromSink.writeShort(toSocket.localPort)
        fromSink.emit()
        logger.log(Level.INFO, "SocksProxy connected $fromAddress to $toAddress")

        // Copy sources to sinks in both directions.

        val id =
          when (i) {
            4 -> 3 // SETTINGS_MAX_CONCURRENT_STREAMS renumbered.
            7 -> 4 // SETTINGS_INITIAL_WINDOW_SIZE renumbered.
            else -> i
          }
        sink.writeShort(id)
        sink.writeInt(settings[i])
      }
      sink.flush()
    }
  }

  /**
   * Send a connection-level ping to the peer. `ack` indicates this is a reply. The data in