use eventgroup to sync spp_vfs_write
each connection has a switch_delay_timer not sharing a one
revert functions like spp_find_slot_by_xxx
fix vfs read bug when peer close
Prevent a remote device from doing a Bluetooth Impersonation Attack
(BIAS) by:
- Preventing remote device to downgrade secure connection
feature mask. Secure connection feature mask should remain same or
increase to enabled in link key generation and authentication.
- Doing a mutual authentication during Legacy Authentication.
Signed-off-by: Chinmay Chhajed <chinmay.chhajed@espressif.com>
