Add unit tests

vendor/google.golang.org/grpc/backoff.go

@@ -17,22 +17,42 @@
  */
 
 // See internal/backoff package for the backoff implementation. This file is
-// kept for the exported types and API backward compatility.
+// kept for the exported types and API backward compatibility.
 
 package grpc
 
 import (
 	"time"
+
+	"google.golang.org/grpc/backoff"
 )
 
 // DefaultBackoffConfig uses values specified for backoff in
 // https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md.
+//
+// Deprecated: use ConnectParams instead. Will be supported throughout 1.x.
 var DefaultBackoffConfig = BackoffConfig{
 	MaxDelay: 120 * time.Second,
 }
 
 // BackoffConfig defines the parameters for the default gRPC backoff strategy.
+//
+// Deprecated: use ConnectParams instead. Will be supported throughout 1.x.
 type BackoffConfig struct {
 	// MaxDelay is the upper bound of backoff delay.
 	MaxDelay time.Duration
 }
+
+// ConnectParams defines the parameters for connecting and retrying. Users are
+// encouraged to use this instead of the BackoffConfig type defined above. See
+// here for more details:
+// https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md.
+//
+// This API is EXPERIMENTAL.
+type ConnectParams struct {
+	// Backoff specifies the configuration options for connection backoff.
+	Backoff backoff.Config
+	// MinConnectTimeout is the minimum amount of time we are willing to give a
+	// connection to complete.
+	MinConnectTimeout time.Duration
+}