@NonNull
    public static Single<Response> getRequest(final String uri, @Nullable final Parameters params, @Nullable final Parameters headers) {
        return request("GET", uri, params, headers, null);
    }
GET HTTP request

@param uri     the URI to request
@param params  the parameters to add to the GET request
@param headers the headers to add to the GET request
@return a single with the HTTP response, or an IOException
main/src/main/java/cgeo/geocaching/network/Network.java