Retrieves the size of a raw file tag attached to the specified vault item.
This method retrieves the size of the binary data held by a raw file tag, identified by TagId, attached to the vault item (file, directory, or alternate stream) specified by FileName. If there isn't a raw file tag with the specified TagId attached to the specified vault item, this method throws an exception.
The value passed for FileName must be a vault-local absolute path. The value passed for TagId must be in the range 0x0001 to 0xCFFF (inclusive).
Please refer to the File Tags topic for more information.
Note: This method can only be called when Active is true.