API architecture for generic callback

interface InputCallbackParams<T extends Message<MessageData> | number[]> {
  message: T;
  deltaTime?: number;
}

export interface InputCallbackOptions {
  callback?: (params: InputCallbackParams<Message<MessageData>>) => void;
  rawCallback?: (params: InputCallbackParams<number[]>) => void;
}

onMessage(
    options: InputCallbackOptions,
  ): void {
    this.callback = Deno.UnsafeCallback.threadSafe(
      RtMidiCCallbackCallbackDefinition,
      (
        deltaTime: number,
        message: Deno.PointerValue<unknown>,
        messageSize: number | bigint,
      ) => {
        const msg_data = new Uint8Array(
          new Deno.UnsafePointerView(message!).getArrayBuffer(
            messageSize as number,
          ),
        );

        if (options.callback !== undefined) {
          options.callback({
            message: decodeMessage(msg_data),
            deltaTime,
          });
        }

        if (options.rawCallback !== undefined) {
          options.rawCallback({
            message: Array.from(msg_data),
            deltaTime,
          });
        }
      },
    );
    rtmidi.rtmidi_in_set_callback(this.device, this.callback!.pointer, null);
  }