Alexander Yastrebov

``` --- FAIL: TestFifo (3.29s) --- FAIL: TestFifo/fifo_with_reaching_max_concurrency_and_queue_timeouts (1.04s) fifo_test.go:260: aroute: * -> fifo(3, 5, "10ms") -> "http://127.0.0.1:39415" fifo_test.go:306: Success [0..1]: 0.10 fifo_test.go:307: requests: 1938 fifo_test.go:311: OK rate too low...

``` --- FAIL: TestFifo (3.29s) --- FAIL: TestFifo/fifo_with_reaching_max_concurrency_and_queue_timeouts (1.03s) fifo_test.go:260: aroute: * -> fifo(3, 5, "10ms") -> "http://127.0.0.1:43297" fifo_test.go:306: Success [0..1]: 0.10 fifo_test.go:307: requests: 1999 fifo_test.go:311: OK rate too low...

``` --- FAIL: TestFifo (3.29s) --- FAIL: TestFifo/fifo_with_reaching_max_concurrency_and_queue_timeouts (1.03s) fifo_test.go:260: aroute: * -> fifo(3, 5, "10ms") -> "http://127.0.0.1:44063" fifo_test.go:306: Success [0..1]: 0.10 fifo_test.go:307: requests: 1991 fifo_test.go:311: OK rate too low...

@szuecs https://github.com/zalando/skipper/pull/2644 apparently did not help

``` --- FAIL: TestFifo (3.30s) --- FAIL: TestFifo/fifo_with_reaching_max_concurrency_and_queue_timeouts (1.03s) fifo_test.go:260: aroute: * -> fifo(3, 5, "10ms") -> "http://127.0.0.1:45581" fifo_test.go:306: Success [0..1]: 0.10 fifo_test.go:307: requests: 1912 fifo_test.go:311: OK rate too low...

Release notes https://go.dev/doc/go1.21

A downside of grouping updates is that a broken update could prevent others, see e.g. https://github.com/zalando/skipper/pull/2436

Also Skipper datasource neither detects duplicate routes from the same dataclient nor between multiple dataclients and overwrites existing route with the latest update which could be shown via: ```diff diff...

Masking could be implemented by hashing the actual value such that masked values still could be grouped.

I have used mocktracer here https://github.com/zalando/skipper/pull/1666#discussion_r547477511 due to the problem with tracingtest