Operation tag decorator for redis and memcache clients

[aliyakamercan]

fixes #513

@benblack86 @DanSimon @dxuhuang @nsauro

[benblack86]

Is there a way to test?

[codecov-io]

Codecov Report

Merging #568 into develop will increase coverage by 0.2%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           develop     #568     +/-   ##
==========================================
+ Coverage    84.75%   84.95%   +0.2%     
==========================================
  Files           98       98             
  Lines         4422     4428      +6     
  Branches       349      352      +3     
==========================================
+ Hits          3748     3762     +14     
+ Misses         674      666      -8

Impacted Files	Coverage Δ
...s/src/main/scala/colossus/service/ServiceDSL.scala	85.41% <100%> (ø)	:arrow_up:
.../main/scala/colossus/protocols/redis/package.scala	44.44% <100%> (+27.77%)	:arrow_up:
...in/scala/colossus/protocols/memcache/package.scala	100% <100%> (ø)	:arrow_up:
.../main/scala/colossus/core/ConnectionSnapshot.scala	0% <0%> (ø)	:arrow_up:
...n/scala/colossus/protocols/redis/RedisServer.scala	100% <0%> (ø)	:arrow_up:
...ossus/protocols/http/streaming/StreamService.scala	82.35% <0%> (ø)	:arrow_up:
...la/colossus/protocols/redis/RedisServerCodec.scala	80% <0%> (ø)	:arrow_up:
...ossus/src/main/scala/colossus/core/DataBlock.scala	95.23% <0%> (ø)	:arrow_up:
...cala/colossus/protocols/http/HttpServerCodec.scala	80% <0%> (ø)	:arrow_up:
...ssus/src/main/scala/colossus/core/DataBuffer.scala	66.66% <0%> (ø)	:arrow_up:
... and 61 more

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[aliyakamercan]

You can start the example http server with a metric sender.

[benblack86]

What I meant was, can you write a test :)