AWSEMFExporter - Only calculate metric rate for cumulative counter. Avoid doing SingleDImensionRollup for metrics with only one dimension.

[shaochengwang]

Description:

1. Make change on the metric rate calculation logic. Only calculate metric rate for cumulative counter.
2. Do not do SingleDImensionRollup for metrics with only one dimension in order to avoid duplicate metrics.

Testing:

make all
make unit-tests-with-cover

Documentation:

1. Remove rate calculation for Gauge and Histogram data because It is not meaningful to calculate the rate for those data types.
2. Do not do SingleDImensionRollup for metrics with only one dimension because those metrics have only one dimension by default. Otherwise, it will generate duplicate metrics with single dimension.

[codecov]

Codecov Report

Merging #1280 into master will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1280      +/-   ##
==========================================
- Coverage   89.02%   89.02%   -0.01%     
==========================================
  Files         297      297              
  Lines       14976    14989      +13     
==========================================
+ Hits        13333    13344      +11     
- Misses       1245     1247       +2     
  Partials      398      398              

Flag	Coverage Δ
#unit	89.02% <100.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
exporter/awsemfexporter/metric_translator.go	92.53% <100.00%> (+0.42%)	⬆️
...eiver/awsxrayreceiver/internal/udppoller/poller.go	97.61% <0.00%> (-2.39%)	⬇️

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[anuraaga]

Can we add unit tests?

[mxiamxia]

LGTM! thanks.