[infogulch]

I wonder if a broadcast could be implemented as a specialization of a ring buffer:

Use 1 ring buffer, and N read pointers. The writer determines how far it can write by taking the minimum of the read pointers. ... I think that's all you'd need? The writer will block if a reader is too slow, but any broadcast that preserves messages and has bounded memory will have that problem. Maybe the difficulties will be in adding and removing readers.