Disable ALPN enforcing.

[zidokobik]

I've noticed that httpx is enforcing ALPN in its TLS handshake even with custom SSLContext. Is there a way to disable this? I want to produce a specific JA3 string for the TLS Client Hello. Enforcing ALPN produces a JA3 hash outside the user's control.

The following code is what I used to inspect with wireshark:

context = ssl.SSLContext(ssl.PROTOCOL_TLSv1_2)
async with AsyncClient(http2=False, follow_redirects=False, verify=context) as c:
	await c.get('https://httpbin.org/')