fn write_varint(out: &mut Vec<u8>, value: u64)Expand description
Appends an unsigned LEB128 varint.
The same encoding didbot_data::Cid uses inside a CID, written
again here rather than shared, because the two are the same shape for
unrelated reasons: multiformats chose it for CIDs and CAR chose it for
section lengths, and a change to either must not move the other.