QueryParams and Headers are both multidicts but behave differently

[rafalkrupinski]

...and I don't mean that one is case sensitive and the other isn't

When receiving multi-valued parameter (httpx client):

server.get('http://example.com', params=httpx.QueryParams([
        ('param', 'value1'),
        ('param', 'value2')
    ]))

request.query_params.keys() returns param once, and I can get each value from request.query_params.getlist('param')

When receiving multi-valued header:

client_server.get('http://example.com', headers=httpx.Headers([
        ('param', 'value1'),
        ('param', 'value2'),
    ]))

request.headers.keys() returns param twice.

Not a critical issue, but confusing. If they share API, they should share behaviour.

[adriangb]

I do think we could unify the APIs to return a single key from .keys().