reduce a reverse stream of ssb messages into a collection of threads and channels.
outputs a data structure that looks like this:
{
roots: {
<thread_root_id>: {
key: <thread_root_id>,
value: <thead_initial_msg>,
replies: [...],
}
},
channels: {
<channel_name>: <thread_id>
}
}
It's assumed that the input is streamed in reverse order, most recent first.
MIT