buffer: fix cancel()

* fix mismatch between return value & read value that would either crash
  or freeze the browser depending on its mood
* add an assertion to detect the above footgun
* fix some resource leaks
* fix iteration over a table that called a function which altered the
  table in buffer's cancel()
* if user cancels before anything is loaded, destroy the container too

0 files changed, 0 insertions, 0 deletions