// However, this scheme is only used for multipart objects that are
// not encrypted.
//
// # Server-side Encryption
//
// S3 specifies three types of server-side-encryption - SSE-C, SSE-S3
// and SSE-KMS - with different semantics w.r.t. ETags.
// In case of SSE-S3, the ETag of an object is computed the same as
// for single resp. multipart plaintext objects. In particular,
// the ETag of a singlepart SSE-S3 object is its content MD5.
//