slower than expected decompression, round 2

[jrevels]

Spiritual successor to #13; not sure what the culprit is this time:

julia> using CodecZstd, TranscodingStreams

julia> bytes = read("fid_1509_2018_LTM.edf.zst");

julia> @time transcode(ZstdDecompressor, bytes);
 27.252612 seconds (594.62 k allocations: 1.858 GiB, 0.02% gc time)

>>> import zstandard as zstd
>>> import timeit
>>> byts = open('fid_1509_2018_LTM.edf.zst', 'rb').read();
>>> d = zstd.ZstdDecompressor()
>>> timeit.timeit("d.decompress(byts)", number=1, globals=globals())
3.793142723850906

[jrevels]

This might be the same issue as #17?

[jrevels]

Yup, it's the same regression as #17. After downgrading to v0.6.0:

julia> @time transcode(ZstdDecompressor, bytes);
  3.765080 seconds (594.58 k allocations: 1.858 GiB, 0.15% gc time)