Function whoami_handler 

async fn whoami_handler(
    __arg0: AuthenticatedClientRequest<Request>,
) -> ArminiusResponse<Response>

Handler for GET /_matrix/client/v3/account/whoami (See https://spec.matrix.org/v1.15/client-server-api/#get_matrixclientv3accountwhoami).

Gets information about the owner of the given access token.