@Override
 protected boolean doEquals(DFB functionBuilder) {
   return Objects.equals(this.fieldName, functionBuilder.getFieldName())
       && Objects.equals(this.functionBytes, functionBuilder.getFunctionBytes())
       && Objects.equals(this.multiValueMode, functionBuilder.getMultiValueMode());
 }
 @Override
 protected DFB doReadFrom(StreamInput in) throws IOException {
   DFB decayFunctionBuilder = createFunctionBuilder(in.readString(), in.readBytesReference());
   decayFunctionBuilder.setMultiValueMode(MultiValueMode.readMultiValueModeFrom(in));
   return decayFunctionBuilder;
 }