you can keep memory

[zhekaus]

extern ArduinoUniqueID _UniqueID; wastes RAM.
Usually, you need to check ID just once. And no need to have it globally.
Please, fix it.

[ricaun]

Hello, I design this way for these reasons:

• Some microcontrollers methods to read serial unique id is slow
• Some libraries use UniqueID on loop
• Need to be simple to use

I think is not a good idea to change the library to gain some RAM, this change could break some codes that use UniqueID more the once.

See yaa!