code: function(type) {
        type = type || defaultType;
        if (this.config) {
          this.config.contentType = type;
          mapInsensitive(this.requestHeaders, 'content-type', type);
          mapInsensitive(this.config.headers, 'content-type', type);
        }
        return this;
      }
docs: Set the content-type for a waiting APICall.
  Note: this has no effect if the APICall has completed.
  @param {string} type The content-type to set. If not specified, this will use 'application/octet-stream'.
  @return {APICall} The current APICall object