pcontext->transfer_map = u_transfer_map_vtbl;
pcontext->transfer_flush_region = u_transfer_flush_region_vtbl;
pcontext->transfer_unmap = u_transfer_unmap_vtbl;
pcontext->transfer_map = u_transfer_map_vtbl;
pcontext->transfer_flush_region = u_transfer_flush_region_vtbl;
pcontext->transfer_unmap = u_transfer_unmap_vtbl;