public static Object clientCall(String jwt, URL url, String method, Object arg) throws IOException {
    return clientCall(jwt, url, method, true, arg);
  }
Performs a Json client call.
@param jwt the jwt token
@param url the url
@param method the http method
@param arg the argument that will be transported as JSon
@return the result the was returned through Json
@throws IOException if marshalling the request/response fail
standalone-metastore/metastore-rest-catalog/src/test/java/org/apache/iceberg/rest/HMSTestBase.java