Windows' `Peripheral::discover_characteristics` does not update list accessible through `Peripheral::characteristics`

[the6p4c]

Describe the bug
After calling Peripheral::discover_characteristics on a device, the list of characteristics returned by Peripheral::characteristics (i.e. the characteristics field in the Peripheral struct in src/winrtble/peripheral.rs) does not update. In fact, there don't appear to be any modifications made to the field, ever.

The list returned by Peripheral::discover_characteristics, however, does contain the correct characteristics.

This results in the README example displaying no characteristics on Windows.

Expected behavior
The list of characteristics returned is updated after they are discovered.

Actual behavior
The list of characteristics returned is not updated, and remains empty.

[qDot]

This should be fixed in both v0.7.3 and v0.8, closing.