Guidance for thread safety

[chmorgan]

I assume I should know this, question is whether calling BLECharacteristic setters and getters from threads other than the one they were created in is safe.

Can’t find any guidance on nimble thread safety (so I assume it isn’t) and didn’t see any guidance here either. I can update the readme if some guidance notes are provided here @h2zero

[h2zero]

All value functions are thread safe, getters make a copy inside a critical section and values are changed inside critical sections.

[chmorgan]

Will close if #367 or something like it lands (or if its rejected as not necessary).

[h2zero]

Commented on PR, thanks!