benchmarks: add metrics benchmark

[iRevive]

Yet another part of the #786.

Baseline

Measurment: average time, lower is better.

SDK is roughly 15% to 30% slower than the OtelJava.

Benchmark                      (backend)       (operation)     (variation)  Mode  Cnt      Score      Error   Units

eightThreadsCommonLabelSet      oteljava      long_counter            noop  avgt   10  28638.180 ±  3617.497   ns/op
eightThreadsCommonLabelSet      oteljava      long_counter  sdk_cumulative  avgt   10  27742.687 ±  1200.754   ns/op
eightThreadsCommonLabelSet      oteljava      long_counter       sdk_delta  avgt   10  28586.511 ±  2407.448   ns/op
eightThreadsCommonLabelSet           sdk      long_counter            noop  avgt   10  26353.959 ±   771.915   ns/op
eightThreadsCommonLabelSet           sdk      long_counter  sdk_cumulative  avgt   10  35163.158 ±   375.981   ns/op
eightThreadsCommonLabelSet           sdk      long_counter       sdk_delta  avgt   10  34662.634 ±   360.655   ns/op

eightThreadsSeparateLabelSets   oteljava      long_counter            noop  avgt   10  26951.976 ±  2104.885   ns/op
eightThreadsSeparateLabelSets   oteljava      long_counter  sdk_cumulative  avgt   10  28151.917 ±  3897.626   ns/op
eightThreadsSeparateLabelSets   oteljava      long_counter       sdk_delta  avgt   10  26909.918 ±   571.061   ns/op
eightThreadsSeparateLabelSets        sdk      long_counter            noop  avgt   10  27774.570 ±  2493.445   ns/op
eightThreadsSeparateLabelSets        sdk      long_counter  sdk_cumulative  avgt   10  35102.793 ±   784.706   ns/op
eightThreadsSeparateLabelSets        sdk      long_counter       sdk_delta  avgt   10  34650.908 ±   320.706   ns/op

oneThread                       oteljava      long_counter            noop  avgt   10   4948.533 ±    81.298   ns/op
oneThread                       oteljava      long_counter  sdk_cumulative  avgt   10   5326.867 ±   277.532   ns/op
oneThread                       oteljava      long_counter       sdk_delta  avgt   10   5255.243 ±   122.588   ns/op
oneThread                            sdk      long_counter            noop  avgt   10   5120.052 ±   223.250   ns/op
oneThread                            sdk      long_counter  sdk_cumulative  avgt   10   6962.334 ±   266.006   ns/op
oneThread                            sdk      long_counter       sdk_delta  avgt   10   7658.263 ±   969.198   ns/op

recordToMultipleAttributes      oteljava      long_counter            noop  avgt   10   5469.453 ±   436.134   ns/op
recordToMultipleAttributes      oteljava      long_counter  sdk_cumulative  avgt   10   7049.623 ±   897.224   ns/op
recordToMultipleAttributes      oteljava      long_counter       sdk_delta  avgt   10   8618.673 ±  4704.295   ns/op
recordToMultipleAttributes           sdk      long_counter            noop  avgt   10   5533.041 ±   118.798   ns/op
recordToMultipleAttributes           sdk      long_counter  sdk_cumulative  avgt   10  11766.431 ±   226.243   ns/op
recordToMultipleAttributes           sdk      long_counter       sdk_delta  avgt   10  11744.749 ±  1033.673   ns/op

This PR

SDK is only 1-10% slower (depending on the number of attributes and concurrency levels).

Benchmark                      (backend)       (operation)     (variation)  Mode  Cnt      Score      Error   Units

eightThreadsCommonLabelSet      oteljava      long_counter            noop  avgt   10  27182.080 ± 2064.094   ns/op
eightThreadsCommonLabelSet      oteljava      long_counter  sdk_cumulative  avgt   10  27002.882 ±  624.538   ns/op
eightThreadsCommonLabelSet      oteljava      long_counter       sdk_delta  avgt   10  26991.866 ±  551.068   ns/op
eightThreadsCommonLabelSet           sdk      long_counter            noop  avgt   10  26568.445 ±  559.356   ns/op
eightThreadsCommonLabelSet           sdk      long_counter  sdk_cumulative  avgt   10  26970.777 ±  534.541   ns/op
eightThreadsCommonLabelSet           sdk      long_counter       sdk_delta  avgt   10  28479.440 ± 3924.062   ns/op

eightThreadsSeparateLabelSets   oteljava      long_counter            noop  avgt   10  31506.592 ± 6814.522   ns/op
eightThreadsSeparateLabelSets   oteljava      long_counter  sdk_cumulative  avgt   10  28212.355 ± 2481.786   ns/op
eightThreadsSeparateLabelSets   oteljava      long_counter       sdk_delta  avgt   10  27082.346 ±  544.882   ns/op
eightThreadsSeparateLabelSets        sdk      long_counter            noop  avgt   10  26845.652 ±  646.818   ns/op
eightThreadsSeparateLabelSets        sdk      long_counter  sdk_cumulative  avgt   10  27930.532 ± 2891.188   ns/op
eightThreadsSeparateLabelSets        sdk      long_counter       sdk_delta  avgt   10  27270.965 ±  606.613   ns/op

oneThread                       oteljava      long_counter            noop  avgt   10   4817.086 ±   47.913   ns/op
oneThread                       oteljava      long_counter  sdk_cumulative  avgt   10   5373.915 ±  165.448   ns/op
oneThread                       oteljava      long_counter       sdk_delta  avgt   10   5137.084 ±   50.088   ns/op
oneThread                            sdk      long_counter            noop  avgt   10   4912.818 ±  295.623   ns/op
oneThread                            sdk      long_counter  sdk_cumulative  avgt   10   5320.152 ±  261.549   ns/op
oneThread                            sdk      long_counter       sdk_delta  avgt   10   5770.930 ±  172.216   ns/op

recordToMultipleAttributes      oteljava      long_counter            noop  avgt   10   5160.638 ±  566.987   ns/op
recordToMultipleAttributes      oteljava      long_counter  sdk_cumulative  avgt   10   5922.355 ±  199.489   ns/op
recordToMultipleAttributes      oteljava      long_counter       sdk_delta  avgt   10   6391.997 ±  249.286   ns/op
recordToMultipleAttributes           sdk      long_counter            noop  avgt   10   5460.340 ±  246.778   ns/op
recordToMultipleAttributes           sdk      long_counter  sdk_cumulative  avgt   10   7095.079 ±  156.089   ns/op
recordToMultipleAttributes           sdk      long_counter       sdk_delta  avgt   10   7142.590 ±  174.927   ns/op