fix buffer allocation for lagacy format

Merge pull request DataDog#143 from DataDog/viq111/1.5.6

Update vendored zstd to 1.5.6

Merge pull request DataDog#132 from DataDog/viq111/bulk-fix-highlycom…

…pressed-payloads

[bulk] Fix being able to Decompress large payloads

Merge pull request DataDog#125 from DataDog/viq111/1.5.5

Update vendored zstd to 1.5.5

context pool

Merge pull request DataDog#117 from bsergean/patch-1

Add SetNbWorkers api to the writer code (see DataDog#108)

Merge pull request DataDog#116 from DataDog/viq111/1.5.2

Update zstd to version 1.5.2

Merge pull request DataDog#115 from DataDog/viq111/decompress-sanity-…

…check

[zstd][DataDog#60] Add decompression size sanity Check

Merge pull request DataDog#105 from DataDog/evan.jones/zstd-legacy

zstd.go: Set ZSTD_LEGACY_SUPPORT=4 to decompress legacy payloads

Merge pull request DataDog#96 from delthas/fix-stream-read

[zstd_stream] Don't block in reader.Read if a zstd block is available