Reports the compression level applied to a writer opened with no compression arguments at
all -- the value set here, or 3 (this library's level for its own default zstd) if it was
never set. Naming a codec explicitly, by argument or by
parquet_set_default_compression, does not attach this level to it; see that procedure.
integer function parquet_get_default_compression_level() result(n) n = cfg_default_compression_level if (n == level_codec_default) n = level_zstd_default end function parquet_get_default_compression_level