Default callback should try to read/write from node metadata. This depends on the implementation of https://github.com/Trrack/trrackjs/issues/37 and https://github.com/Trrack/trrackjs/issues/38
Default callback should try to read/write from node metadata.
This depends on the implementation of Trrack/trrackjs#37 and Trrack/trrackjs#38