[Feature Request] Extended Advertising

[zxzxwu]

Extended Advertising support is not completed yet.

TODO:

• Start / Stop advertising set
  • Add support for LE Extended Advertising #334
• Improve legacy and extended advertising objects
• Handle HCI_LE_ADVERTISING_SET_TERMINATED_EVENT
  • Add advertiser classes and handle adv set terminated events #366
• Virtual self test
  • controller extended advertising #238

[zxzxwu]

@barbibulle I am wondering whether #238 is still needed. In our practice, tests could be achieved with mocking.