pub fn insert_input(
        &mut self,
        name: String,
        input: InputSession<Time, Vec<V>, Diff>,
        trace: KeysOnlyHandle<V>)
    {
        self.inputs.sessions.insert(name.clone(), input);
        self.traces.set_unkeyed(&Plan::Source(name), &trace);
    }
Inserts a new input session by name.
interactive/src/manager.rs