v3: Add a comment about retry (motdotla#758)

Author: abetomo

lib/main.js

@@ -19,7 +19,14 @@ const CloudWatchLogs = require(path.join(__dirname, 'cloudwatch_logs'))
 const AWSXRay = require('aws-xray-sdk-core')
 const { createNamespace } = require('continuation-local-storage')
 
-// Migrating to v3.
+/*
+ * Migrating to v3.
+ *
+ * # About retry
+ * By default, each client already has a default retry strategy.
+ * The default retry count is 3, and only retryable errors will be retried.
+ * https://docs.aws.amazon.com/sdkref/latest/guide/feature-retry-behavior.html
+ */
 const { LambdaClient, CreateFunctionCommand } = require('@aws-sdk/client-lambda')
 const lambdaClient = new LambdaClient()
 
@@ -693,7 +700,6 @@ Emulate only the body of the API Gateway event.
 
   _uploadNew (lambda, params) {
     if (process.env.USE_AWS_SDK_V3) {
-      // todo retry
       console.log('DEBUG: Use AWS SDK V3: CreateFunctionCommand()')
       const command = new CreateFunctionCommand(params)
       return lambdaClient.send(command)