Add batch logging support to eventlog.

client/cmd/isolate/exp_archive.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package main
 
 import (
         "context"
         "encoding/json"
         "errors"
@@ skipping 200 matching lines @@
         if err := ioutil.WriteFile(archiveOpts.Isolated, isolJSON, 0644); err != nil {
                 return err
         }
         isolatedHash := string(isolated.HashBytes(isolJSON))
         fmt.Printf("%s\t%s\n", isolatedHash, filepath.Base(archiveOpts.Isolated))
 
         end := time.Now()
 
         if endpoint := eventlogEndpoint(c.isolateFlags.EventlogEndpoint); endpoint != "" {
                 ctx := context.Background()
-                logger := eventlog.NewClient(endpoint)
+                logger := eventlog.NewClient(ctx, endpoint)
 
                 // TODO(mcgreevy): fill out more stats in archiveDetails.
                 archiveDetails := &logpb.IsolateClientEvent_ArchiveDetails{
                         IsolateHash: []string{isolatedHash},
                 }
                 if err := logStats(ctx, logger, start, end, archiveDetails); err != nil {
                         log.Printf("Failed to log to eventlog: %v", err)
                 }
         }
 
@@ skipping 62 matching lines @@
 func eventlogEndpoint(endpointFlag string) string {
         switch endpointFlag {
         case "test":
                 return eventlog.TestEndpoint
         case "prod":
                 return eventlog.ProdEndpoint
         default:
                 return endpointFlag
         }
 }