According to RFC 2616 and RFC 2326 individual protocol elements, like
headers and except the actual content, are terminated by using CRLF.
Therefore the test data files for these protocols need to contain
mixed line-endings if the actual protocol elements use CRLF while
the file uses LF.
When a connection is no longer used, it is kept in the cache. If the
cache is full, the oldest idle connection is closed. If no connection is
idle, the current one is closed instead.
