private String connect(String host, Port port) throws IOException {
    return selector.connect(new InetSocketAddress(host, port.getPort()), networkConfig.socketSendBufferBytes,
        networkConfig.socketReceiveBufferBytes, port.getPortType());
  }
Start creating a connection to a host using {@link Selector#connect}.
@param host the hostname to connect to.
@param port the port to connect to.
@return the connection ID.
@throws IOException if DNS resolution fails on the hostname or if the server is down
ambry-network/src/main/java/com/github/ambry/network/SocketNetworkClient.java