pub unsafe extern "C" fn CPLVirtualMemDerivedNew(
    pVMemBase: *mut CPLVirtualMem,
    nOffset: vsi_l_offset,
    nSize: vsi_l_offset,
    pfnFreeUserData: CPLVirtualMemFreeUserData,
    pCbkUserData: *mut c_void
) -> *mut CPLVirtualMem