Add Metrics API and aggregator #2978

Job	Run time
ruby-versions / Generate Ruby versions	2s
Ruby 2.4 & Rack 2, options - null	57s
Ruby 2.4 & Rack 3, options - null	56s
Ruby 2.5 & Rack 2, options - null	58s
Ruby 2.5 & Rack 3, options - null	56s
Ruby 2.6 & Rack 2, options - null	2m 13s
Ruby 2.6 & Rack 3, options - null	2m 18s
Ruby 2.7 & Rack 2, options - null	1m 7s
Ruby 2.7 & Rack 3, options - null	1m 4s
Ruby 3.0 & Rack 2, options - null	46s
Ruby 3.0 & Rack 3, options - null	50s
Ruby 3.1 & Rack 2, options - null	47s
Ruby 3.1 & Rack 3, options - null	59s
Ruby 3.2 & Rack 2, options - null	44s
Ruby 3.2 & Rack 3, options - null	52s
Ruby 3.3 & Rack 2, options - null	53s
Ruby 3.3 & Rack 3, options - null	1m 1s
Ruby head & Rack 2, options - null	47s
Ruby head & Rack 3, options - null	39s
Ruby jruby & Rack 2, options - null	2m 6s
Ruby jruby & Rack 3, options - null	1m 58s
Ruby jruby-head & Rack 2, options - null	2m 14s
Ruby jruby-head & Rack 3, options - null	2m 1s
Ruby 3.2 & Rack 0, options - null	46s
Ruby 3.2 & Rack 2, options - null	1m 2s
Ruby 3.2 & Rack 3, options - { "rubyopt": "--enable-frozen-string-literal --debug=frozen-string-literal" }	44s
Ruby 3.2 & Rack 3, options - { "codecov": 1 }	48s
	30m 28s

Provide feedback