Rewrite debouncer using coroutines

Use coroutines and conflated channels to re-implement the debouncer.

Some noteworthy links:
* https://gist.github.com/k-kagurazaka/54441d6d5dfdb5668fd884008cd480a2
* https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.channels/-channel/index.html

The issue names no file, test, or entry point. Start by locating the existing debouncer and reviewing the linked coroutine and channel references; done means the debouncer is reimplemented with coroutines and conflated channels while preserving its current behavior.

Written by the indexing model from the issue text.