code: public AddToTextIndexRequestBuilder addAdditionalMetadata(final Object metadatum, final Object... metadata) {
          this.additionalMetadata.add(metadatum);
          this.additionalMetadata.addAll(Arrays.asList(metadata));
  
          return this;
      }
docs: Sets the value of the metadata parameter
  
  @param metadatum The first index
  @param metadata  The remaining metadata
  @return this