if (bytes != null) {
if (checksum == 0) {
checksum = _keyConverter.contentHashFor(bytes);
_checksum.set(checksum);
}
return bytes.withBytes(BodyCallback.instance);
}
File f = _content.contentAsFile();
if (f != null) {
try {
return new BodyFileBacked(f, _content.length(), _checksum);