get blobContentMD5() {
        return this.originalResponse.blobContentMD5;
    }
If the blob has a MD5 hash, and if
request contains range header (Range or x-ms-range), this response header
is returned with the value of the whole blob's MD5 value. This value may
or may not be equal to the value returned in Content-MD5 header, with the
latter calculated from the requested range.

@readonly