tndb is a tiny library for creating and reading constant databases
with key/value data pairs. Main features:

* low overhead:
  - database header size is about 30 bytes
  - 5 extra bytes per record (key length is limited to 256 bytes)

* compressed (gzip and zstd are supported) databases are handled transparently

* built-in data integrity verification - file's digest is computed
  during database creation and could be verified before opening database
  for reading.
