Compute Space Needed for Clone

This function computes the space required (in bytes) to clone a virtual disk, after possible format conversion.
vixError = VixDiskLib_SpaceNeededForClone(child.Handle(), VIXDISKLIB_DISK_VMFS_FLAT, &spaceReq);
VixDiskLib_SpaceNeededForClone()
might not give accurate results, or could return
VIX_E_INVALID_ARG
, when used with thin provisioned disk type
VIXDISKLIB_DISK_VMFS_THIN
.