Otherwise curl would have to guess where the body ends.
<data>
HTTP/1.1 407 Authorization Required to proxy me my dear\r
Proxy-Authenticate: Digest realm="weirdorealm", nonce="12345"\r
+Content-Length: 33\r
\r
And you should ignore this data.
</data>
<datacheck>
HTTP/1.1 407 Authorization Required to proxy me my dear\r
Proxy-Authenticate: Digest realm="weirdorealm", nonce="12345"\r
+Content-Length: 33\r
\r
HTTP/1.1 200 OK swsbounce\r
Server: no