Enhanced the chunking and error handling inside the buffer functions.

This also reduces the pause on transfers under certain conditions.

Submitted by:	Dean Gaudet, Roy Fielding
Reviewed by:	Dean Gaudet, Roy Fielding, Ralf S. Engelschall


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3@78912 13f79535-47bb-0310-9956-ffa450edef68