Ensures data is flushed to the underlying medium using IStream::Commit.
_StreamCommit(ByRef $oStream[, $grfCommitFlags])
| $oStream | IStream COM object. |
| $grfCommitFlags | [optional] Commit flags (default: $STGC_DEFAULT). |
| Success: | 1 |
| Failure: | 0, sets @error to: 1 - Invalid stream object. 2 - COM error (HRESULT in @extended). |