$ ed -s CSV.jl/src/file.jl <<<'567,575p'
        if !ctx.threaded && ctx.ntasks > 1 && !ctx.silencewarnings
            # !ctx.threaded && ctx.ntasks > 1 indicate that multithreaded parsing failed.
            # Thes messages echo the corresponding debug statement in the definition of ctx
            if numwarnings[] > 0
                @warn "Multithreaded parsing failed and fell back to single-threaded parsing, check previous warnings for possible reasons."
            else
                @error "Multithreaded parsing failed and fell back to single-threaded parsing. This can happen if the input contains multi-line fields; otherwise, please report this issue."
            end
        end
$ 

$ ed -s CSV.jl/test/write.jl <<<'345,350p'
    # parition writing
    io = IOBuffer()
    io2 = IOBuffer()
    CSV.write([io, io2], Tables.partitioner((default_table, default_table)); partition=true)
    @test String(take!(io)) == "col1,col2,col3\n1,4,7\n2,5,8\n3,6,9\n"
    @test String(take!(io2)) == "col1,col2,col3\n1,4,7\n2,5,8\n3,6,9\n"
$

$ find CSV.jl/test/testfiles -type f | grep -oE '\.(\w+)$' | sort -u
.cscv
.csv
.dat
.gz
.tsv
.txt
.wsv
$