reuse runtimeAPIClient.buffer

[shogo82148]

Issue #, if available:

runtimeAPIClient.buffer is defined on here

aws-lambda-go/lambda/runtime_api_client.go

Line 32 in 55dc88b

buffer *bytes.Buffer

but it is never used.

Description of changes:

runtimeAPIClient.next() is never called concurrently, so we can reuse runtimeAPIClient.buffer.
It avoids extra re-allocation.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-commenter]

Codecov Report

Merging #325 into master will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #325   +/-   ##
=======================================
  Coverage   72.46%   72.46%           
=======================================
  Files          18       18           
  Lines         730      730           
=======================================
  Hits          529      529           
  Misses        136      136           
  Partials       65       65           

Impacted Files	Coverage Δ
lambda/runtime_api_client.go	75.00% <100.00%> (ø)

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[bmoffatt]

Nice catch, thanks! This was the original intent, but I think I missed it during an internal refactor :)