class SimpleCov::ParallelAdapters::GenericAdapter

does after the no-op returns.
the resultset cache, which ‘SimpleCov.wait_for_parallel_results`
runner-provided API the only synchronization available is polling
`wait_for_siblings` is inherited from Base as a no-op — without a
as a non-first worker.
(zero-based runners that start at 1). Any other value is treated
is `“”` (parallel_tests/parallel_rspec convention) or `“1”`
Heuristic for `first_worker?`: the worker whose `TEST_ENV_NUMBER`
be loaded.
when `TEST_ENV_NUMBER` is set; doesn’t require any specific gem to
knapsack-style splitters, custom CI sharding scripts). Activates
don’t ship a Ruby API for SimpleCov to hook (parallel_rspec,
‘TEST_ENV_NUMBER` / `PARALLEL_TEST_GROUPS` env-var convention but
Catch-all adapter for parallel test runners that follow the

def active? 

def active?
  return false if SimpleCov.parallel_tests == false
  ENV.key?("TEST_ENV_NUMBER")
end

def expected_worker_count 

def expected_worker_count
  ENV["PARALLEL_TEST_GROUPS"]&.to_i || 1
end

def first_worker?

"1" for the first worker. Both shapes match.
parallel_rspec inherits that. Runners that number from 1 use
parallel_tests sets the first worker's TEST_ENV_NUMBER to ""; 
def first_worker?
  ["", "1"].include?(ENV.fetch("TEST_ENV_NUMBER", nil))
end