public HttpRequest useProxy(final String proxyHost, final int proxyPort) {
    if (connection != null)
      throw new IllegalStateException("The connection has already been created. This method must be called before reading or writing to the request.");

    this.httpProxyHost = proxyHost;
    this.httpProxyPort = proxyPort;
    return this;
  }
Configure an HTTP proxy on this connection. Use {{@link #proxyBasic(String, String)} if
this proxy requires basic authentication.

@param proxyHost
@param proxyPort
@return this request
lib/src/main/java/com/github/kevinsawicki/http/HttpRequest.java