Due to historical reasons, the dumper was built to dump the data in a very specific binary format. This can and will change in the future, ideally to a standardized format like protobuf. However, for now, this document records the binary format that the files are dumped with, so that any populator can be written to understand this format.
The key dump is just the output of lru_crawler metadump <all/hash> which is basically a single key and its associated metadata per line.
The Data dump enters the following for each memcached key/value pair. (NO spaces between fields; NO delimiters between KV pairs)
<keylen (2-bytes)> <expiry (4-bytes)> <flag (4-bytes)> <datalen (4-bytes)>
Until a populator is available as part of this project, writing any application that can read the following binary format and writing it to memcached would suffice. See MemcachedUtils::CraftMetadataString() for the writer part.