Why doesn't .on() accept a fromBlock like web3js?

[samlaf]

I have 2 related questions:

1. Does provider.on() works differently with a jsonrpc and a ws provider? I've only quickly browsed the code, but it seems like in both cases, it just uses the eth_getLogs method (see code) instead of eth_subscribe.

2. Why doesn't provider.on() accept a fromBlock (similar to how web3js does it)? My use case for this is that I want to listen to all events starting at a given block, and then continue subscribing to the newer events. How can I go about doing this in ethersjs to receive the events chronologically (first ones first)? Since provider.on() will just start polling from the current block, I would need to also do a queryFilter from the starting block to the one when provider.on() was called. But in this case I would receive these first events potentially after some of the newer events received on provider.on()? It just seems a bit ugly... is there a cleaner way to do this?