Revert "last_write_len must not be 0, which makes weight useless"
Revert "last_write_len must not be 0, which makes weight useless"

This reverts commit e260006182067ef0f34523f13f64481b32e52314.

lukw00/nghttp2,thinred/nghttp2,wzyboy/nghttp2,serioussam/nghttp2,lukw00/nghttp2,icing/nghttp2,serioussam/nghttp2,wzyboy/nghttp2,icing/nghttp2,lukw00/nghttp2,wzyboy/nghttp2,serioussam/nghttp2,thinred/nghttp2,serioussam/nghttp2,serioussam/nghttp2,lukw00/nghttp2,thinred/nghttp2,icing/nghttp2,serioussam/nghttp2,lukw00/nghttp2,thinred/nghttp2,serioussam/nghttp2,lukw00/nghttp2,wzyboy/nghttp2,icing/nghttp2,wzyboy/nghttp2,icing/nghttp2,icing/nghttp2,icing/nghttp2,lukw00/nghttp2,thinred/nghttp2,thinred/nghttp2,wzyboy/nghttp2,thinred/nghttp2,wzyboy/nghttp2