investigate Context's syscalls usage

[Geal]

creating a new Context object surprisingly implies doing a file syscall:

This is apparently due to DashMap looking up the available resources in the cgroup at creation: https://github.com/xacrimon/dashmap/blob/459db7ac6f3d0b46f507cb724dd9bb0ce389f4ae/src/lib.rs#L55

I opened https://github.com/xacrimon/dashmap/issues/219 to see if this could be memoized. If not we could do it inside the router

[Geal]

this will be fixed once https://github.com/xacrimon/dashmap/pull/222 is merged and published

[Geal]

closing this because DashMap 5.4.0 was released with a fix for that and added to the router in https://github.com/apollographql/router/commit/01512853c25441b1dcd58a51562aa8677e37b73e