Non-blocking ap_get_brigade() doesn't return EAGAIN?

[Jacob Champion]

The patchset I recently folded into mod_websocket [1] rails the CPU 
when using ws:// instead of wss://. The problem appears to be that an 
empty non-blocking read from ap_get_brigade() returns EAGAIN when using 
SSL, but without SSL it is returning SUCCESS with an empty brigade.

Yann, I noticed that you wrote about something similar a while ago [2] 
but I don't know if that conversation went anywhere. Is SUCCESS with an 
empty brigade really a correct postcondition for ap_get_brigade(), or is 
this a bug?

--Jacob

[1] 
http://mail-archives.apache.org/mod_mbox/httpd-modules-dev/201509.mbox/%3C55F1F089.4020101%40gmail.com%3E
[2] 
http://mail-archives.apache.org/mod_mbox/httpd-dev/201310.mbox/%3CCAKQ1sVMCA_C5wsP_ApOK_XGTQxyqN_=QYLEQ7jrq6ikeP=8...@mail.gmail.com%3E