wsi timeout, wsi hrtimer, sequencer timeout and vh-protocol timer
all now participate on a single sorted us list.
The whole idea of polling wakes is thrown out, poll waits ignore the
timeout field and always use infinite timeouts.
Introduce a public api that can schedule its own callback from the event
loop with us resolution (usually ms is all the platform can do).
Upgrade timeouts and sequencer timeouts to also be able to use us resolution.
Introduce a prepared fakewsi in the pt, so we don't have to allocate
one on the heap when we need it.
Directly handle vh-protocol timer if LWS_MAX_SMP == 1
There are quite a few linked-lists of things that want events after
some period. This introduces a type binding an lws_dll2 for the
list and a lws_usec_t for the duration.
The wsi timeouts, the hrtimer and the sequencer timeouts are converted
to use these, also in the common event wait calculation.
lws_dll2 removes the downsides of lws_dll and adds new features like a
running member count and explicit owner type... it's cleaner and more
robust (eg, nodes know their owner, so they can casually switch between
list owners and remove themselves without the code knowing the owner).
This deprecates lws_dll, but since it's public it allows it to continue
to be built for 4.0 release if you give cmake LWS_WITH_DEPRECATED_LWS_DLL.
All remaining internal users of lws_dll are migrated to lws_dll2.
Adapt service loops and event libs to use microsecond waits
internally, for hrtimer and sequencer. Reduce granularity
according to platform / event lib wait.
Add a helper so there's a single place to extend it.
https://github.com/warmcat/libwebsockets/issues/1550
rx flow control needs to handle the situation that it is draining from
a previous rx flow control period, and the user code reasserts rx flow
control partway through that.
The accounting for the used rx then boils down to only trimming the
rxflow buflist we were "replaying" to consume however much we managed
to deliver of that this time before the rx flow control came again.
"Normal" rx consumption is wrong in this case, since we accounted for
it entirely in the rxflow cache buflist.
The patch recognizes this situation, does the accounting in the cache
buflist, and then lies to the caller that there was no rx consumption
to be accounted for at his level.
With SMP as soon as we add the new sockfd to the fds table, in the
case we load-balanced the fd on to a different pt, service on it
becomes live immediately and concurrently. This can lead to the
unexpected situation that while we think we're still initing the
new wsi from our thread, it can have lived out its whole life
concurrently from another service thread.
Add a volatile flag to inform the owning pt that if it wants to
service the wsi during this init window, it must wait and retry
next time around the event loop.
On h1, cgi stdout close doesn't prompt the http close, instead it
times out. Fix that so we also close on h1, and make the close
action itself on http timeout less drastic.
As it was, GnuTLS actually marks the close as a fatal TLS error.
