Calculates the wire size of the SAFEARRAY object, and gets the SAFEARRAY handle and data.
ULONG __RPC_USER LPSAFEARRAY_UserSize(
[in] Points to data used by RPC.
[in] Sets the buffer offset so that the SAFEARRAY object is properly aligned when it is marshaled to the buffer.
[in] Points to the safe array that contains the data to marshal.
The return value obtained from the returned HRESULT is one of the following.