Sets the last access time of a vault item.
This method sets the last access time of the vault item (file, directory, symbolic link, or alternate stream) specified by FileName.
The value passed for FileName must be a vault-local absolute path.
The LastAccessTime parameter specifies the new last access time for the vault item, which must be specified in UTC.
Note: This method can only be called when Active is true, and cannot be called within events.