Padding is not handled gracefully

[maleadt]

MWE:

using CodecBzip2: transcode, Bzip2Compressor, Bzip2Decompressor

function main()
    # generate some data
    input = Pipe()
    output = Pipe()
    cmd = `bzip2`
    proc = run(pipeline(cmd, stdout=output, stdin=input); wait=false)
    close(output.in)
    writer = @async begin
        write(input, "Hello, world!")
        close(input)
    end
    reader = @async read(output)
    wait(proc)
    compressed = fetch(reader)

    # add some padding
    push!(compressed, 0)

    # verify we can decompress using `bunzip2`
    mktempdir() do dir
        path = joinpath(dir, "test.bz2")
        write(path, compressed)
        run(`bunzip2 $path`)
        println(read(joinpath(dir, "test"), String))
    end

    uncompressed = transcode(Bzip2Decompressor, compressed)
    String(uncompressed)
end

The bunzip2 tool generates a warning, but continues to decompress:

bunzip2: /var/folders/5m/zq0fq7r91f7_5qb1c31vgy5h0000gn/T/jl_B16lhs/test.bz2: trailing garbage after EOF ignored
Hello, world!

CodecBzip2.jl fails:

ERROR: CodecBzip2.BZ2Error(-5)

... where -5 seems to be BZ_DATA_ERROR_MAGIC.