public RequestConfig build() {
            return new RequestConfig(
                    expectContinueEnabled,
                    proxy,
                    cookieSpec,
                    redirectsEnabled,
                    circularRedirectsAllowed,
                    maxRedirects,
                    authenticationEnabled,
                    targetPreferredAuthSchemes,
                    proxyPreferredAuthSchemes,
                    connectionRequestTimeout != null ? connectionRequestTimeout : DEFAULT_CONNECTION_REQUEST_TIMEOUT,
                    connectTimeout,
                    responseTimeout,
                    connectionKeepAlive != null ? connectionKeepAlive : DEFAULT_CONN_KEEP_ALIVE,
                    contentCompressionEnabled,
                    hardCancellationEnabled,
                    protocolUpgradeEnabled,
                    unixDomainSocket);
        }
Sets the Unix Domain Socket path to use for the connection.
<p>
When set, the connection will use the specified Unix Domain Socket
instead of a TCP socket. This is useful for communicating with local
services like Docker or systemd.
</p>
<p>
Default: {@code null}
</p>

@return this instance.
@since 5.6
httpclient5/src/main/java/org/apache/hc/client5/http/config/RequestConfig.java