code: function TransactionBuilder(apiClient) {
      
      if (typeof apiClient.namespace === "undefined" || apiClient.namespace === null) {
          throw new Error("The API client has not been initialized");
      }
      
      this.client = apiClient;
      this.records = [];
      this.keys = [];
      this.metadata = ByteBuffer.fromHex("");
  }
docs: Provides the ability to build an Openchain mutation.
  
  @constructor
  @param {!ApiClient} apiClient The API client representing the endpoint on which the mutation should be submitted.