public static JavaSysPropsProxySettings createHttpProxy(String propertyPrefix, int defaultPort) {
        return new JavaSysPropsProxySettings(
            ProxyType.HTTP,
            "http.nonProxyHosts",
            System.getProperty(propertyPrefix + ".proxyHost"),
            SystemPropertyUtil.getInt(propertyPrefix + ".proxyPort", defaultPort),
            SystemPropertyUtil.get(propertyPrefix + ".proxyUser"),
            SystemPropertyUtil.get(propertyPrefix + ".proxyPassword")
        );
    }
Initialise HTTP proxy settings from Java System Properties.

@param propertyPrefix the property prefix (e.g. `foo.proxyhost`, `foo` is prefix).
                      Likely should be `http` or `https` unless you are doing something esoteric.
@param defaultPort the default proxy port (should one not be found in the system properties)
gateway/platforms/vertx3/vertx3/src/main/java/io/apiman/gateway/platforms/vertx3/engine/proxy/JavaSysPropsProxySettings.java