High Throughput Append Blob (#21424)

* adding test for highthroughput appendblob

* recorded test

* Unrecord file, update CHANGELOG.md

sdk/storage/azblob/CHANGELOG.md

@@ -8,6 +8,7 @@
 * Added [FilterBlobs by Tags](https://learn.microsoft.com/rest/api/storageservices/find-blobs-by-tags-container) API for container client.
 * Added `System` option to `ListContainersInclude` to allow listing of system containers (i.e, $web).
 * Updated the SAS Version to `2021-12-02` and added `Encryption Scope` to Account SAS, Service SAS, and User Delegation SAS
+* Content length limit for `AppendBlob.AppendBlock()` and `AppendBlob.AppendBlockFromURL()` raised from 4 MB to 100 MB.
 
 ### Breaking Changes
 

sdk/storage/azblob/appendblob/client_test.go

@@ -125,6 +125,36 @@ func (s *AppendBlobRecordedTestsSuite) TestAppendBlock() {
 	_require.Equal(*appendResp.BlobCommittedBlockCount, int32(2))
 }
 
+func (s *AppendBlobUnrecordedTestsSuite) TestAppendBlockHighThroughput() {
+	_require := require.New(s.T())
+	testName := s.T().Name()
+	svcClient, err := testcommon.GetServiceClient(s.T(), testcommon.TestAccountDefault, nil)
+	_require.NoError(err)
+
+	containerName := testcommon.GenerateContainerName(testName)
+	containerClient := testcommon.CreateNewContainer(context.Background(), _require, containerName, svcClient)
+	defer testcommon.DeleteContainer(context.Background(), _require, containerClient)
+
+	abName := testcommon.GenerateBlobName(testName)
+	abClient := containerClient.NewAppendBlobClient(testcommon.GenerateBlobName(abName))
+
+	// Create AppendBlob with 5MB data
+	_, err = abClient.Create(context.Background(), nil)
+	_require.Nil(err)
+	contentSize := 5 * 1024 * 1024 // 5MB
+	r, sourceData := testcommon.GetDataAndReader(testName, contentSize)
+	appendResp, err := abClient.AppendBlock(context.Background(), streaming.NopCloser(r), nil)
+	_require.Nil(err)
+	_require.NotNil(appendResp.ETag)
+
+	// Check data integrity through downloading.
+	destBuffer := make([]byte, contentSize)
+	downloadBufferOptions := blob.DownloadBufferOptions{Range: blob.HTTPRange{Offset: 0, Count: int64(contentSize)}}
+	_, err = abClient.DownloadBuffer(context.Background(), destBuffer, &downloadBufferOptions)
+	_require.Nil(err)
+	_require.Equal(destBuffer, sourceData)
+}
+
 func (s *AppendBlobUnrecordedTestsSuite) TestAppendBlockWithAutoGeneratedCRC64() {
 	_require := require.New(s.T())
 	testName := s.T().Name()