Bug: Uploading a file with VFileInput throws an error

[DavidBerger98]

With versions of trame-server>2.2.0 uploading a file with vuetify.VFileInput throws an error on the client saying Method result cannot be serialized.

But the handle method is still executed correctly.

To reproduce:

from trame.app import get_server
from trame.ui.vuetify import SinglePageWithDrawerLayout
from trame.widgets import vuetify
from trame.app.file_upload import ClientFile


server = get_server()


with SinglePageWithDrawerLayout(server) as layout:
    with layout.toolbar:
        vuetify.VFileInput(
            v_model=("file_exchange", None),
        )


@server.state.change("file_exchange")
def handle(file_exchange, **kwargs):
    file = ClientFile(file_exchange)
    print(file.info)


server.start()