// 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
// access the ETag by looking for the HTTP response header key "Etag".
// However, some of them assume that the header key has to be "ETag"
// (case-sensitive) and will fail otherwise.
// Further, some clients require that the ETag value is a double-quoted