[grpc-objc] close all http2 connexion

[benjamin....@gmail.com]

Hi, i'm trying to close all tcp / http2 connexions for a gRPC objective-c client  for when my app goes in background (i want absolutely 0 activity in this case). Calling "cancel" on the GRPCall closes ongoing gRPC streams, but doesn't close the underlying tcp connexion (i guess because reusing the connexion is an optimization).

What function should i call to manually close everything ? Of course, once my app goes back to foreground i want to be able to reopen all connections, just like when first launching the app. 

Thanks a lot

Benjamin G.