Things that were underspecified in the spec/whitepaper:

- nonce: 24 or 32 bytes? (impl is 24, spec says 32)
- endianness of magic (big-endian)
- uppercase/lowercase of algorithm name (inconsistent in one place)
- what if there is only a single chunk/entry in a register tree? then a leaf
  acts as a root?
- unclear where protobuf schema actually lives...
- "append only" is mentioned many times, but need to write "back in" to merkel
  tree on many occasions
- inconsistent message names between .proto and whitepaper
- protocol extension stuff not in the whitepaper
- whitepaper should be versioned/tagged, or marked as "work in progress"
- encryption not really covered in whitepaper... seems to be XSalsa20 XOR'd
  with data
- "ping" mechanism: sending a 0 byte

"You can use the byteOffset property in the Stat meta- data object to seek into
the right position in the content for the start of this chunk." => unnecessary,
node.js specific?

"If you are sharing multiple hypercores on the same port you can use this event
to wait for the remote peer to indicate which hypercore they are interested inj"

Clarify: appending to tree SLEEP results in writes into middle of file (for
root nodes). This seems not-great for performance (can't bulk-write). Better to
cache or work in RAM then batch commit?

varint-encoded message prefix for network messages still feels sort of
inefficient... fixed 32-bit length makes more sense to me, seems like
efficiency gains would be pretty small. would need benchmarking.
  https://developers.google.com/protocol-buffers/docs/techniques#streaming


### Small Bugs

hypercore: 'Request' without 'Have' crashes dat, despite whitepaper saying "You
should only send Have messages to peers who have expressed interest in this
region with Want messages.":

    /usr/lib/node_modules/dat/node_modules/hypercore/lib/replicate.js:119
            if (!self.remoteBitfield.set(request.index, true)) return
                                    ^

    TypeError: Cannot read property 'set' of null
        at onvalue (/usr/lib/node_modules/dat/node_modules/hypercore/lib/replicate.js:119:33)
        at onread (/usr/lib/node_modules/dat/node_modules/random-access-file/index.js:130:14)
        at FSReqWrap.wrapper [as oncomplete] (fs.js:629:17)