@Override
    public String toString() {
        return new StringJoiner(", ", SysPropsProxySelector.class.getSimpleName() + "[", "]")
            .add("httpProxy=" + httpProxy)
            .add("httpsProxy=" + httpsProxy)
            .add("socksProxy=" + socksProxy)
            .toString();
    }
Resolve a proxy, if there is one.

@param resourceUri the URI that will be assessed against the proxy configuration
@return the proxy, if there is an appropriate one configured, and it is not on the non-proxy list.
gateway/platforms/vertx3/vertx3/src/main/java/io/apiman/gateway/platforms/vertx3/engine/proxy/SysPropsProxySelector.java