code: public <T> T callFunction(
        final String name,
        final List<?> args,
        final @Nullable Long requestTimeout,
        final Decoder<T> decoder) {
      return this.functionService.callFunction(name, args, requestTimeout, decoder);
    }
docs: Calls the specified Stitch function, and decodes the response into a value using the provided
  {@link Decoder}.
  
  @param name the name of the Stitch function to call.
  @param args the arguments to pass to the Stitch function.
  @param requestTimeout the number of milliseconds the client should wait for a response from the
  server before failing with an error.
  @param decoder the {@link Decoder} to use to decode the Stitch response into a value.
  @param <T> the type into which the Stitch response will be decoded.
  @return the decoded value.