Modify buff.h and buff.c to enable modules to intercept the output byte stream for dynamic page caching. A pointer to a 'filter callback' function is added to the end of buff.h. This function, if registered by a module, is called at the top of buff_write() and writev_it_all().
MMN Minor bumped.
Obtained from: [Kevin Mallory <email@example.com> Reviewed by: Bill Stoddard