SyncResponseHandlerAdapter: Prevent overflow

[rschmitt]

SyncResponseHandlerAdapter requests Long.MAX_VALUE from its
Publisher, not just initially upon subscription but also on every
#onNext call. This means that every Subscription implementation that
does not take steps to prevent overflow (or which throws an exception if
overflow is detected) will eventually see the number of outstanding
requests go negative, and will stop consuming data. Larger responses
require more calls to #onNext and are therefore more likely to
encounter this issue.

The fix is simply to request new messages individually, so that the
number of outstanding requests always hovers around Long.MAX_VALUE.

I confirm that this pull request can be released under the Apache 2 license.

[dagnir]

Thanks!

[codecov-io]

Codecov Report

Merging #1542 into master will increase coverage by 0.02%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master    #1542      +/-   ##
============================================
+ Coverage     74.96%   74.98%   +0.02%     
  Complexity      770      770              
============================================
  Files           882      882              
  Lines         27429    27481      +52     
  Branches       2140     2157      +17     
============================================
+ Hits          20561    20607      +46     
- Misses         5897     5907      +10     
+ Partials        971      967       -4

Flag	Coverage Δ	Complexity Δ
#unittests	74.98% <100%> (+0.02%)	770 <0> (ø)	⬇️

Impacted Files	Coverage Δ	Complexity Δ
...core/internal/http/async/AsyncResponseHandler.java	88.88% <100%> (ø)	0 <0> (ø)	⬇️
...tomization/CodegenCustomizationProcessorChain.java	81.81% <0%> (-8.19%)	0% <0%> (ø)
...on/awssdk/protocols/ion/AwsIonProtocolFactory.java	72.72% <0%> (-5.06%)	0% <0%> (ø)
.../software/amazon/awssdk/core/sync/RequestBody.java	89.65% <0%> (-3.21%)	0% <0%> (ø)
...ftware/amazon/awssdk/codegen/internal/Jackson.java	59.09% <0%> (-2.82%)	0% <0%> (ø)
...on/awssdk/codegen/internal/DocumentationUtils.java	75% <0%> (-2.42%)	0% <0%> (ø)
...db/mappingclient/extensions/WriteModification.java	52% <0%> (-2.17%)	5% <0%> (ø)
...rvices/s3/internal/ConfiguredS3SdkHttpRequest.java	46.15% <0%> (-1.85%)	0% <0%> (ø)
...o/netty/internal/utils/BetterFixedChannelPool.java	52.48% <0%> (-1.66%)	0% <0%> (ø)
...amodb/mappingclient/operations/ConditionCheck.java	41.66% <0%> (-1.2%)	3% <0%> (ø)
... and 33 more

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