add empty-valued header

[curme]

Expected behavior

I want to add a header with empty value, for example, my request requires a header 'Authorization: ' which is a 'Authorization' header valued as ''.

url = 'xxx.xxxx.com'
headers = {'Content-Type': 'application/json', 'Authorization': ''}
self.crawl(url, callback=self.xxx_handle, method='POST', headers=headers)

Actual behavior

However, actually, the header 'Authorization' seems to be kicked out because it's empty.

Maybe, it might cause by lib 'libcurl', which I found linux command 'curl' has the same behavior:
curl --request GET 'https://github.com/binux/pyspider' --header 'Accept: */*' --header 'Authorization: ' -v

In the curl printed log, we could find that 'Authorization' header was removed:
> GET /binux/pyspider HTTP/1.1
> Host: github.com
> User-Agent: curl/7.61.0
> Accept: */*
>

I want to add empty-valued header into request. Any suggestions?
Thanks a lot!

[curme]

I found that curl has already supported sending empty header by replacing the colon with a semicolon. Exactly in the case I provided above, we could do in this way:
curl --request GET 'https://github.com/binux/pyspider' --header 'Accept: */*' --header 'Authorization;' -v

log:
> GET /binux/pyspider HTTP/1.1
> Host: github.com
> User-Agent: curl/7.61.0
> Accept: */*
> Authorization:
>

Which means 'libcurl' enables users to send empty header in request (BTW I suppose pyspider also rely on 'libcurl').
But I still haven found how to do in pyspider. Need your help