This is only relevant when automating a plugin-bypass, due to
ActiveChanged the following could happen from the realtime thread:
#2 ARDOUR::Session::update_latency_compensation (false, false)
#3 PBD::Signal0<void, PBD::OptionalLastValue<void> >
#4 ARDOUR::AutomationControl::actually_set_value
#5 ARDOUR::PluginInsert::PluginControl::actually_set_value
#6 ARDOUR::PluginInsert::connect_and_run
#7 ARDOUR::PluginInsert::automate_and_run
In this specific case the update_latency_compensation()
is called with process-lock held but the caller lied:
called_from_backend=false
When a delayline update is needed, this can lead to a deadlock,
since the process-lock is acquired again.
Simply postponing the update is preferable since this also
postpones the change when actively recording.
PS. This may need special casing for freewheel export.