Inconsistent use of protocol specific options

Setting protocol specific options has been a convenient method for overriding the default options for each protocol. E.g., the Azure blob storage implementation behaves peculiarly and requires setting anon=False to use the credentials in the environment (https://github.com/fsspec/adlfs/issues/348).

So for paths provided by an application, we might do:

fsspec.open(..., az={"anon": False})

This option is ignored for local paths, and used for az:// protocol urls, and therefore allows us to configure defaults for each protocol. Unfortunately, this doesn't work with https(s) protocol urls, since the kwargs are directly forwarded to aiohttp, e.g. https://github.com/fsspec/filesystem_spec/blob/561428ca18a9865d8f63fe188a590d791ec52c92/fsspec/implementations/http.py#L826

• If this is an intended usage mode: How about dropping all protocol specific kwargs before forwarding to the http implementation?
• If this is not an intended feature: How can we set per protocol defaults otherwise? If we have to manually parse the URLs and assign different kwargs to the fsspec.open method the convinience of this API greatly diminishes.

Either way, I'm happy to contribute code if we can agree on a solution.

Start with fsspec.open and the HTTP implementation at fsspec/implementations/http.py around the referenced line, then trace how protocol-specific options reach aiohttp. Confirm whether dropping those options for HTTP is the intended behavior or determine the alternative for per-protocol defaults; done requires an agreed solution and corresponding tests.