Recently, during a project that involved downloading a file from AWS S3 using C#, I discovered there were several ways to accomplish this task. In particular, I had three methods at my disposal: TransferUtility.DownloadAsync, DownloadSingleFileAsync, and GetObjectAsync.

Intrigued by these options, I decided to delve deeper and consult our trusty friend Google Bard for insights. The quest was to determine which method would emerge as the most efficient and scalable solution for our needs.

According to Google Bard, it became evident that the TransferUtility.DownloadAsync method was a notable choice. The TransferUtility.DownloadAsync method is designed to be more efficient and scalable than the DownloadSingleFileAsync and GetObjectAsync methods.

The TransferUtility.DownloadAsync method is more efficient and more scalable because it uses a background thread pool to download the file. This means that the download can be performed in the background, without blocking the main thread. This can improve performance, especially for large files.

The TransferUtility.DownloadAsync method is also more scalable because it can handle multiple downloads simultaneously. This means that it can be used to download files from Amazon S3 in parallel, which can improve performance for applications that need to download a large number of files.

The DownloadSingleFileAsync and GetObjectAsync methods do not use a background thread pool, so they are less efficient and less scalable. They also do not support resumable downloads, which can make them less reliable.

Here is a table that summarizes the differences between the TransferUtility.DownloadAsync method and the DownloadSingleFileAsync and GetObjectAsync methods:

PurposeDownloads a single fileDownloads a single fileDownloads a single file or a directory
ArgumentName of the fileName of the objectName of the object
Return valueTask objectStream objectIAmazonS3Object object
EfficiencyMore efficientLess efficientLess efficient
ScalabilityMore scalableLess scalableLess scalable
Resumable downloadsSupportedNot supportedNot supported
Uses a background thread poolYesNoNo
Supports multiple downloads simultaneouslyYesNoNo
Supports resumable downloadsYesNoNo

While I haven’t directly examined the C# code from the AWS SDK, I believe this result from Google Bard provides valuable insights. I will update this blog post if I get new findings.

In my use case, where I only need to download a single file, I opted for TransferUtility.DownloadAsync. It’s simpler, resulting in a more concise code with fewer lines.