9-Asynchronous-EN.md

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Asynchronous Call

Open asynchronous call

Alibaba Cloud Go SDK supports opening asynchronous calls in two ways： Note: After opening the asynchronous call, you need to call Shutdown() before you can start the asynchronous call again

1. Enable asynchronous call when initializing client

   import (
       "github.com/aliyun/alibaba-cloud-sdk-go/sdk"
       "github.com/aliyun/alibaba-cloud-sdk-go/sdk/auth/credentials"
       "github.com/aliyun/alibaba-cloud-sdk-go/services/ecs"
   )
   
   c := sdk.NewConfig()
   c.EnableAsync = true // Asynchronous task switch
   c.GoRoutinePoolSize = 10 // Number of goroutines
   c.MaxTaskQueueSize = 20 // Maximum number of tasks for a single goroutine
   c.Timeout = 10 * time.Second
   credential := credentials.NewAccessKeyCredential("acesskeyid", "accesskeysecret")
   client, err := ecs.NewClientWithOptions("regionid", c, credential)

2. Enable asynchronous call when calling EnableAsync

   // the first parameter is the maximum number of goroutines
   // the second parameter is the maximum number of tasks for a single goroutine
   // EnableAsync is only allowed to be called once, unless the Shutdown() method is used to first close the asynchronous call, and then call EnableAsync
   client.EnableAsync(10, 20)

Make an asynchronous call

Alibaba Cloud Go SDK supports asynchronous calls in two ways：

1. Using channel as return values

   responseChannel, errChannel := client.FooWithChan(request)
   
   // this will block
   response := <-responseChannel
   err = <-errChannel

2. Use callback to control the callback

   blocker := client.FooWithCallback(request, func(response *FooResponse, err error) {
       // handle the response and err
   })
   
   // blocker which is type of (chan int)，is used to control synchronization，when returning 1 means success，and returning 0 means failure.
   // When <-blocker returns failure，err also will be handled by afferent callback.
   result := <-blocker

Close asynchronous call

Use the function of client to close asynchronous call and the goroutines

client.Shutdown()

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