Allow to set a debounce rate for messages

[christian-bromann]

Let's say we have the following use case:

import Channel from 'tangle/worker_threads';

interface TodoList {
    todos: string[]
    dueDate: number
}

const ch = new Channel<TodoList>('foobar', {
    todos: [],
    dueDate: Date.now()
});

and given we update the state with two separate calls, e.g.:

ch.broadcast({ dueDate: Date.now() });
ch.broadcast({ todos: [{...}] });

If someone listens on todos, this would cause two event listener executions, one with no updates, the other with the updated todos. This is bad for performance for two reasons: 1) a state update is triggered without an update to the state, 2) multiple individual updates trigger individual event listener executions.

To improve this behavior I suggest to:

• only broadcast updates if a state property has changed
• allow to set up a debounce rate so tangle collects changes over x amount of time and broadcast the current state after the debounce limit is reached