// a very high probability.
//
// Therefore, an S3 implementation may encrypt an ETag before storing
// it. In this case, the stored ETag may not be a well-formed S3 ETag.
// For example, it can be larger due to a checksum added by authenticated
// encryption schemes. Such an ETag must be decrypted before sent to an
// S3 client.
//
// # S3 Clients
//
// There are many different S3 client implementations. Most of them