public byte[] toBytes() {

      try {
        return objectMapper.writeValueAsBytes(this);
      } catch (JsonProcessingException e) {
        throw new IllegalArgumentException("Unable to encode as string: " + this, e);
      }
    }
Arbitrary application-specific JSON metadata in the archive.
<p>
stores name, attribution, created_at, planetiler build SHA, vector_layers, etc.
planetiler-core/src/main/java/com/onthegomap/planetiler/pmtiles/Pmtiles.java