Removed the warnings, instead have a sync.Map where they are
registered/unregistered and can be inspected with an undocumented
monitor page.
Added the notion of "in progress" which is the number of messages
that have beend pop()'ed. When recycle() is invoked this count
goes down.
Signed-off-by: Ivan Kozlovic <ivan@synadia.com>
When a consumer is configured with "meta-only" option, and the
stream was backed by a memory store, a memory corruption could
happen causing the application to receive corrupted headers.
Also replaced most of usage of `append(a[:0:0], a...)` to make
copies. This was based on this wiki:
https://github.com/go101/go101/wiki/How-to-efficiently-clone-a-slice%3F
But since Go 1.15, it is actually faster to call make+copy instead.
Signed-off-by: Ivan Kozlovic <ivan@synadia.com>