Reproduced with client version 1.1.1 and mongodb server version 3.6.18

If a default write concern is set up on client:

let mut opts = ClientOptions::parse(&url).await?;
let wc = WriteConcern::builder().w(Acknowledgment::Majority).journal(true).build();
opts.write_concern = Some(wc);
let client = Client::with_options(opts)?;

And then that client is used to preform a command that doesn't support writeConcern:

client.database(db).collection(coll)
  .count_documents(filter, None).await?

Command will fail with an error:

Command failed (InvalidOptions): Command does not support writeConcern

I've tried to set some `CountOptions` instead of using None, but it did not help.

Workaround is to do not use a global WriteConcern, and set it on each request when needed, but IMO global wc is there for a reason, and this is a bug. Not sure if this is related to the somewhat ancient version of mongodb server I've tested this on, but it is officially supported by the rust driver as far as I know.