You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: transfer_from_azure.go
    path of file: ./repos/golang-samples/storagetransfer
    
    the code of the file until where you have to start completion: // Copyright 2023 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions an
    
func transferFromAzure(w io.Writer, projectID string, azureStorageAccountName string, azureSourceContainer string, gcsSinkBucket string) (*storagetransferpb.TransferJob, error) {
	// Your Google Cloud Project ID.
	// projectID := "my-project-id"

	// The name of your Azure Storage account.
	// azureStorageAccountName := "my-azure-storage-acc"

	// The name of the Azure container to transfer objects from.
	// azureSourceContainer := "my-source-container"

	// The name of the GCS bucket to transfer objects to.
	// gcsSinkBucket := "my-sink-bucket"

	ctx := context.Background()
	client, err := storagetransfer.NewClient(ctx)
	if err != nil {
		return nil, fmt.Errorf("storagetransfer.NewClient: %w", err)
	}
	defer client.Close()

	// The Azure SAS token, should be accessed via environment variable for security
	azureSasToken := os.Getenv("AZURE_SAS_TOKEN")

	req := &storagetransferpb.CreateTransferJobRequest{
		TransferJob: &storagetransferpb.TransferJob{
			ProjectId: projectID,
			TransferSpec: &storagetransferpb.TransferSpec{
				DataSource: &storagetransferpb.TransferSpec_AzureBlobStorageDataSource{
					AzureBlobStorageDataSource: &storagetransferpb.AzureBlobStorageData{
						StorageAccount: azureStorageAccountName,
						AzureCredentials: &storagetransferpb.AzureCredentials{
							SasToken: azureSasToken,
						},
						Container: azureSourceContainer,
					},
				},
				DataSink: &storagetransferpb.TransferSpec_GcsDataSink{
					GcsDataSink: &storagetransferpb.GcsData{BucketName: gcsSinkBucket}},
			},
			Status: storagetransferpb.TransferJob_ENABLED,
		},
	}
	resp, err := client.CreateTransferJob(ctx, req)
	if err != nil {
		return nil, fmt.Errorf("failed to create transfer job: %w", err)
	}
	if _, err = client.RunTransferJob(ctx, &storagetransferpb.RunTransferJobRequest{
		ProjectId: projectID,
		JobName:   resp.Name,
	}); err != nil {
		return nil, fmt.Errorf("failed to run transfer job: %w", err)
	}
	fmt.Fprintf(w, "Created and ran transfer job from %v to %v with name %v", azureSourceContainer, gcsSinkBucket, resp.Name)
	return resp, nil
}