C++ async and futures in Mbed-os

it looks like C++ features like async programming can be used already, I have found Tests that make use of this extensions.
Can you recommend some readings about this or is there a tutorial for this? I have not played yet with this features, is it advisable to use them or is the overhead in std lib to much?

Edit:
ok, it does not work. The async calls were used in the unit tests which run on a host system.