Lock a region of bytes in the stream.
Source position: types.pp line 512
| function IStream.LockRegion( | 
| libOffset: LargeUint; | 
| cb: LargeUint; | 
| dwLockType: DWORD | 
| ):HRESULT; | 
LockRegion locks a region of the storage, starting at libOffset, for cbCount bytes. The applied lock is of type dwLockType. The function returns zero if the lock was successfully applied.
On error, a nonzero exit code is returned.