The implementation in STM works well and certainly ticks the battle-tested box:

https://hackage.haskell.org/package/stm-2.4.4.1/docs/Control-Concurrent-STM-TChan.html#v:newBroadcastTChan


What does the following comment in the documentation really mean (highlighted by >>><<<)?

"Create a write-only TChan. >>> More precisely, readTChan will retry even after items have been written to the channel.<<< The only way to read a broadcast channel is to duplicate it with dupTChan."



-- Saurabh.