It iterates over the wrapped transports until it finds one
that implements the CloseIdleConnections method and executes it.
add test for closeidle http1 connections
add test for http1.1 reconnect with inflight request
add test to reuse connection request
add test for request connect after timeout
add test for client-go request concurrency
Kubernetes-commit: b9d865a8185b62d83e9ff81b0e3499a26ac6960d