HTTP/2 to the hosts your secrets name

A sandbox's HTTPS requests to a host that one of your secrets names now go over HTTP/2 when your client and the host both offer it, as they already did to every other host. Concurrent calls to that host share one connection instead of each taking one of the sandbox's connections, and gRPC works there too. Each request is still checked on its own: its host, its rules and where the value goes. See security.