public TlsConfig build() {
            return new TlsConfig(
                    handshakeTimeout,
                    supportedProtocols,
                    supportedCipherSuites,
                    versionPolicy != null ? versionPolicy : HttpVersionPolicy.NEGOTIATE);
        }
Determines the HTTP protocol policy. By default, connections are expected to use TLS ALPN
extension to negotiate the application protocol to be used by both endpoints.
<p>
Default: {@link HttpVersionPolicy#NEGOTIATE}
</p>

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