add NewBackendsWithConfig helper (#1748)

stripe.go

@@ -1116,8 +1116,7 @@ func Int64Slice(v []int64) []*int64 {
 	return out
 }
 
-// NewBackends creates a new set of backends with the given HTTP client. You
-// should only need to use this for testing purposes or on App Engine.
+// NewBackends creates a new set of backends with the given HTTP client.
 func NewBackends(httpClient *http.Client) *Backends {
 	apiConfig := &BackendConfig{HTTPClient: httpClient}
 	connectConfig := &BackendConfig{HTTPClient: httpClient}
@@ -1129,6 +1128,16 @@ func NewBackends(httpClient *http.Client) *Backends {
 	}
 }
 
+// NewBackendsWithConfig creates a new set of backends with the given config for all backends.
+// Useful for setting up client with a custom logger and http client.
+func NewBackendsWithConfig(config *BackendConfig) *Backends {
+	return &Backends{
+		API:     GetBackendWithConfig(APIBackend, config),
+		Connect: GetBackendWithConfig(ConnectBackend, config),
+		Uploads: GetBackendWithConfig(UploadsBackend, config),
+	}
+}
+
 // ParseID attempts to parse a string scalar from a given JSON value which is
 // still encoded as []byte. If the value was a string, it returns the string
 // along with true as the second return value. If not, false is returned as the