//	 e2 := MD5(part-2)
//	...
//	 eN := MD5(part-N)
//
// Then, the ETag of the object is computed as MD5 of all individual
// part checksums. S3 also encodes the number of parts into the ETag
// by appending a -<number-of-parts> at the end:
//
//	ETag := MD5(e1 || e2 || e3 ... || eN) || -N
//
//	For example: ceb8853ddc5086cc4ab9e149f8f09c88-5
//
// However, this scheme is only used for multipart objects that are