code: function(imageIdentifier, data, callback, method) {
          var url = this.getMetadataUrl(imageIdentifier);
  
          request({
              method: method || 'POST',
              uri: this.getSignedResourceUrl(method || 'POST', url),
              json: data,
              onComplete: function(err, res, body) {
                  callback(err, body, res);
              }
          });
  
          return this;
      }
docs: Edit metadata of an image
  
  @param {String}   imageIdentifier
  @param {Object}   data
  @param {Function} callback
  @param {String}   method HTTP method to use (POST/PUT)
  @return {ImboClient}