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.
Since the messages are queued and then read in order from the event loop
thread, it's not generally safe to pass pointers to argument structs,
since there's no guarantee the lifetime of the thing sending the message
lasted until the sequencer read the message.
This puts pressure on the single void * argument-passed-as-value... this patch
adds a second void * argument-passed-as-value so it's more possible to put
what's needed directly in the argument.
It's also possible to alloc the argument on the heap and have the sequencer
callback free it after it has read it.
Add a generic table-based backoff scheme and a helper to track the
try count and calculate the next delay in ms.
Allow lws_sequencer_t to be given one of these at creation time...
since the number of creation args is getting a bit too much
convert that to an info struct at the same time.
SMTP was improved to use the new abstract stuff a while ago,
but it was only implemented with raw socket abstract transport,
and a couple of 'api cheats' remained passing network information
for the peer connection through the supposedly abstract apis.
This patch adds a flexible generic token array to supply
abstract transport-specific information through the abstract apis,
removing the network information from the abstract connect() op.
The SMTP minimal example is modified to use this new method to
pass the network information.
The abstract transport struct was opaque, but there are real
uses to override it in user code, so this patch also makes it
part of the public abi.
