Description:
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This bug report forms part of an attempt to test and fix the implementation of HTTP/1.1 in the HTTP stream wrapper. See http://marc.info/?l=php-internals&m=147544280019519&w=2

A "100 Continue" response is *usually* only sent in response to an "Expect: 100-continue" header, and *usually* only useful with requests which have a body (e.g. POST, PUT). As such, it is unlikely to be encountered by someone sending a GET request using e.g. file_get_contents, but this is not guaranteed.

According to RFC 7231 section 6.2:

> A client MUST be able to parse one or more 1xx responses received
> prior to a final response, even if the client does not expect one.  A
> user agent MAY ignore unexpected 1xx responses.

However, the code currently treats these statuses as errors:

> HTTP request failed! HTTP/1.1 100 Continue