Relax typing to allow for http.RoundTripper

registry/client.go

@@ -55,7 +55,7 @@ func NewClient(services *disco.Disco, creds auth.CredentialsSource, client *http
 		client.Timeout = requestTimeout
 	}
 
-	services.Transport = client.Transport.(*http.Transport)
+	services.Transport = client.Transport
 
 	return &Client{
 		client:   client,

svchost/disco/disco.go

@@ -40,9 +40,9 @@ type Disco struct {
 	hostCache map[svchost.Hostname]Host
 	credsSrc  auth.CredentialsSource
 
-	// Transport is a custom http.Transport to use.
+	// Transport is a custom http.RoundTripper to use.
 	// A package default is used if this is nil.
-	Transport *http.Transport
+	Transport http.RoundTripper
 }
 
 func NewDisco() *Disco {