> We don't set any `Content-Type` in the client. It is more
> consistent with our other JSON-RPC use to set it to `application/json`.
>
> Note that our server doesn't enforce content types, so it doesn't make a
> difference in practice. But it is fairly strange HTTP behavior to not set it.
>
> This came up in #18950.
This is a backport of core#20055