Modify the conformance test driver to support outgoing responses.
They are returned for incoming requests in order.
Add a test that returns a file resource, which involves the server
sending a roots/list request to the client.
Change-Id: Ie7eb69a8c99ccbf11721518cfffb21244c03e532
Reviewed-on: https://go-review.googlesource.com/c/tools/+/677475
Commit-Queue: Jonathan Amsterdam <jba@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Robert Findley <rfindley@google.com>
2b9c6bff50