Unloads a bank asynchronously.
Refer to 概説 for a discussion on using strings and IDs.
AK_Success if scheduling successful (use a callback to be notified when completed)
The sound engine internally calls GetIDFromString(in_pszString) to retrieve the bank ID, then it calls the synchronous version of UnloadBank() by ID. Therefore, in_pszString should be the real name of the SoundBank (with or without the BNK extension - it is trimmed internally), not the name of the file (if you changed it), nor the full path of the file.
In order to force the memory deallocation of the bank, sounds that use media from this bank will be stopped. This means that streamed sounds or generated sounds will not be stopped.
Memory pointer from where the bank was initially loaded from. (REQUIRED to determine which bank associated to a memory pointer must be unloaded). Pass NULL only if NULL was passed when loading the bank.
Callback cookie (reserved to user, passed to the callback function)