Sorry, does this mean that their own duckdb format already supports async or doesn't?
Disclaimer: I'm the DuckDB developer who implemented Async I/O for parquet, csvs and the DuckDB Format.
> Other formats, such as JSON files and DuckDB's native database format, use synchronous I/O.
For the future:
> Most of its benefit comes from accessing remote data, but cold local reads can also benefit, albeit less. Next, we plan to add async reads for JSON and DuckDB-native files, as these are the two other formats most relevant to DuckDB core. Formats that live in out-of-tree extensions are not on the roadmap yet.