Merge r1860260 from trunk:

 * modules/http2: more copying of data to disentangle worker processing from main connection


Submitted by: icing
Reviewed by: icing, covener, jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1861247 13f79535-47bb-0310-9956-ffa450edef68