This commit adds the IRQ_GATTS_INDICATE_DONE BLE event which will be raised
with the status of gatts_indicate (unlike notify, indications require
acknowledgement).
An example of its use is added to ble_temperature.py, and to the multitests
in ble_characteristic.py.
Implemented for btstack and nimble bindings, tested in both directions
between unix/btstack and pybd/nimble.
The goal of this commit is to allow using ble.gatts_notify() at any time,
even if the stack is not ready to send the notification right now. It also
addresses the same issue for ble.gatts_indicate() and ble.gattc_write()
(without response). In addition this commit fixes the case where the
buffer passed to write-with-response wasn't copied, meaning it could be
modified by the caller, affecting the in-progress write.
The changes are:
- gatts_notify/indicate will now run in the background if the ACL buffer is
currently full, meaning that notify/indicate can be called at any time.
- gattc_write(mode=0) (no response) will now allow for one outstanding
write.
- gattc_write(mode=1) (with response) will now copy the buffer so that it
can't be modified by the caller while the write is in progress.
All four paths also now track the buffer while the operation is in
progress, which prevents the GC free'ing the buffer while it's still
needed.
