Fix flaky specs

[solnic]

Issue Description

This issue gathers random failures we get from some flaky tests.

Failure 01

• Ruby 3.3

Failures:

  1) Sentry::Client integrated error handling testing with HTTPTransport #capture_event when sending events in background causes error captures client report for transaction event with span counts
     Failure/Error: expect(client.transport).to have_recorded_lost_event(:network_error, 'transaction')
       expected #<Sentry::HTTPTransport:0x00007fad0197b5e8 @logger=#<Logger:0x00007fad0197b868 @level=0, @progname=ni...nt_reports=true, @discarded_events={}, @last_client_report_sent=2025-01-24 10:01:40.480909663 +0000> to have recorded lost event :network_error and "transaction"
     # ./spec/sentry/client/event_sending_spec.rb:492:in `block (5 levels) in <top (required)>'
     # ./spec/sentry/client/event_sending_spec.rb:359:in `block (4 levels) in <top (required)>'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:124:in `block in run'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:110:in `run'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec_ext/rspec_ext.rb:12:in `run_with_retry'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:37:in `block (2 levels) in setup'

  2) Sentry::Client integrated error handling testing with HTTPTransport #capture_event when sending events in background causes error captures client report for error event
     Failure/Error: expect(client.transport).to have_recorded_lost_event(:network_error, 'error')
       expected #<Sentry::HTTPTransport:0x00007fad00bd46b0 @logger=#<Logger:0x00007fad00bd48e0 @level=0, @progname=ni...nt_reports=true, @discarded_events={}, @last_client_report_sent=2025-01-24 10:01:41.297596915 +0000> to have recorded lost event :network_error and "error"
     # ./spec/sentry/client/event_sending_spec.rb:486:in `block (5 levels) in <top (required)>'
     # ./spec/sentry/client/event_sending_spec.rb:359:in `block (4 levels) in <top (required)>'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:124:in `block in run'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:110:in `run'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec_ext/rspec_ext.rb:12:in `run_with_retry'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:37:in `block (2 levels) in setup'

  3) Sentry::Client integrated error handling testing with HTTPTransport #capture_event when sending events in background causes error swallows and logs Sentry::ExternalError (caused by transport's networking error)
     Failure/Error: expect(string_io.string).to match(/Event sending failed: Failed to open TCP connection/)

       expected "D, [2025-01-24T10:01:41.915649 #2632] DEBUG -- sentry: Initializing the Sentry background worker wit...entry: [Transport] Sending envelope with items [event] 14d88737df1a4ab7b8581c7189f963e2 to Sentry\n" to match /Event sending failed: Failed to open TCP connection/
       Diff:
       @@ -1,3 +1,5 @@
       -/Event sending failed: Failed to open TCP connection/
       +D, [2025-01-24T10:01:41.915649 #2632] DEBUG -- sentry: Initializing the Sentry background worker with 2 threads
       +D, [2025-01-24T10:01:41.915735 #2632] DEBUG -- sentry: Sentry HTTP Transport will connect to http://sentry.localdomain/
       +D, [2025-01-24T10:01:41.919898 #2632] DEBUG -- sentry: [Transport] Sending envelope with items [event] 14d88737df1a4ab7b8581c7189f963e2 to Sentry
     # ./spec/sentry/client/event_sending_spec.rb:471:in `block (5 levels) in <top (required)>'
     # ./spec/sentry/client/event_sending_spec.rb:359:in `block (4 levels) in <top (required)>'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:124:in `block in run'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:110:in `run'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec_ext/rspec_ext.rb:12:in `run_with_retry'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/3.3.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:37:in `block (2 levels) in setup'

Finished in 12.55 seconds (files took 0.73758 seconds to load)
1076 examples, 3 failures, 1 pending

Failed examples:

rspec ./spec/sentry/client/event_sending_spec.rb:489 # Sentry::Client integrated error handling testing with HTTPTransport #capture_event when sending events in background causes error captures client report for transaction event with span counts
rspec ./spec/sentry/client/event_sending_spec.rb:483 # Sentry::Client integrated error handling testing with HTTPTransport #capture_event when sending events in background causes error captures client report for error event
rspec ./spec/sentry/client/event_sending_spec.rb:467 # Sentry::Client integrated error handling testing with HTTPTransport #capture_event when sending events in background causes error swallows and logs Sentry::ExternalError (caused by transport's networking error)

Failure 02

• jruby / rack3

  1) Sentry::Client#event_from_exception sets threads interface without stacktrace
     Failure/Error: expect(thread[:name]).to eq("Thread 1")

       expected: "Thread 1"
            got: nil

       (compared using ==)
     # ./spec/sentry/client_spec.rb:370:in `block in <main>'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/jruby/3.1.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:124:in `block in run'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/jruby/3.1.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:110:in `run'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/jruby/3.1.0/gems/rspec-retry-0.6.2/lib/rspec_ext/rspec_ext.rb:12:in `run_with_retry'
     # /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/jruby/3.1.0/gems/rspec-retry-0.6.2/lib/rspec/retry.rb:37:in `block in setup'

Finished in 31.92 seconds (files took 4.12 seconds to load)

Failures 03

Ruby 2.6

Randomized with seed 4066

/home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry/transport/http_transport.rb:69:in `rescue in send_data': end of file reached (Sentry::ExternalError)
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry/transport/http_transport.rb:32:in `send_data'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry/transport.rb:65:in `send_envelope'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry/transport.rb:173:in `flush'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry/client.rb:101:in `flush'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry-ruby.rb:271:in `close'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry-ruby.rb:245:in `block in init'
/opt/hostedtoolcache/Ruby/2.6.10/x64/lib/ruby/2.6.0/net/protocol.rb:225:in `rbuf_fill': end of file reached (EOFError)
	from /opt/hostedtoolcache/Ruby/2.6.10/x64/lib/ruby/2.6.0/net/protocol.rb:191:in `readuntil'
	from /opt/hostedtoolcache/Ruby/2.6.10/x64/lib/ruby/2.6.0/net/protocol.rb:201:in `readline'
	from /opt/hostedtoolcache/Ruby/2.6.10/x64/lib/ruby/2.6.0/net/http/response.rb:40:in `read_status_line'
	from /opt/hostedtoolcache/Ruby/2.6.10/x64/lib/ruby/2.6.0/net/http/response.rb:29:in `read_new'
	from /opt/hostedtoolcache/Ruby/2.6.10/x64/lib/ruby/2.6.0/net/http.rb:1509:in `block in transport_request'
	from /opt/hostedtoolcache/Ruby/2.6.10/x64/lib/ruby/2.6.0/net/http.rb:1506:in `catch'
	from /opt/hostedtoolcache/Ruby/2.6.10/x64/lib/ruby/2.6.0/net/http.rb:1506:in `transport_request'
	from /opt/hostedtoolcache/Ruby/2.6.10/x64/lib/ruby/2.6.0/net/http.rb:1479:in `request'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry/net/http.rb:35:in `request'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry/transport/http_transport.rb:52:in `block in send_data'
	from /opt/hostedtoolcache/Ruby/2.6.10/x64/lib/ruby/2.6.0/net/http.rb:920:in `start'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry/transport/http_transport.rb:49:in `send_data'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry/transport.rb:65:in `send_envelope'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry/transport.rb:173:in `flush'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry/client.rb:101:in `flush'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry-ruby.rb:271:in `close'
	from /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/lib/sentry-ruby.rb:245:in `block in init'
Stopped processing SimpleCov as a previous error not related to SimpleCov has been detected
Coverage report generated for RSpec to /home/runner/work/sentry-ruby/sentry-ruby/sentry-ruby/coverage/coverage.xml. 10539 / 10898 LOC (96.71%) covered.
/opt/hostedtoolcache/Ruby/2.6.10/x64/bin/ruby -I/home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/2.6.0/gems/rspec-core-3.13.2/lib:/home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/2.6.0/gems/rspec-support-3.13.2/lib /home/runner/work/sentry-ruby/sentry-ruby/vendor/bundle/ruby/2.6.0/gems/rspec-core-3.13.2/exe/rspec --pattern spec/\*\*\{,/\*/\*\*\}/\*_spec.rb  --exclude-pattern spec/isolated/\*\*/\*_spec.rb --order rand failed