Don't leak Tempfile instances.

[ioquatix]

Tempfile uses a finalizer that calls unlink which can be offloaded, and can be cancelled, resulting in the following log:

 describe Async::HTTP::Protocol::HTTP10 it behaves like a protocol with multiple client requests describe Async::HTTP::Protocol::HTTP10 it behaves like a protocol with multiple client requests it doesn't cancel all requests test/async/http/protocol/http10.rb:10:575 /home/samuel/.gem/ruby/3.4.0/gems/console-1.31.0/lib/console/filter.rb:169: warning: Exception in finalizer #<Tempfile::FinalizerManager:0x00007f5354070d38 @open_files={}, @path="/tmp/20250713-47323-4bqv5i", @pid=47323, @unlinked=false> /home/samuel/Developer/socketry/async/lib/async/scheduler.rb:244:in 'IO::Event::Selector::URing#transfer': Async::Stop (Async::Stop) from /home/samuel/Developer/socketry/async/lib/async/scheduler.rb:244:in 'Async::Scheduler#block' from /home/samuel/Developer/socketry/async/lib/async/scheduler.rb:59:in 'IO::Event::WorkerPool#call' from /home/samuel/Developer/socketry/async/lib/async/scheduler.rb:59:in 'Async::Scheduler::BlockingOperationWait#blocking_operation_wait' from /home/samuel/.rubies/ruby-head/lib/ruby/3.5.0+2/tempfile.rb:392:in 'File.unlink' from /home/samuel/.rubies/ruby-head/lib/ruby/3.5.0+2/tempfile.rb:392:in 'Tempfile::FinalizerManager#call' from /home/samuel/.gem/ruby/3.4.0/gems/console-1.31.0/lib/console/filter.rb:169:in 'Kernel#is_a?' from /home/samuel/.gem/ruby/3.4.0/gems/console-1.31.0/lib/console/filter.rb:169:in 'Console::Filter#enabled?' from /home/samuel/.gem/ruby/3.4.0/gems/console-1.31.0/lib/console/filter.rb:47:in 'block (3 levels) in []' from /home/samuel/.gem/ruby/3.4.0/gems/console-1.31.0/lib/console/interface.rb:33:in 'Console::Interface#debug' from /home/samuel/.gem/ruby/3.4.0/gems/async-pool-0.10.3/lib/async/pool/controller.rb:272:in 'Async::Pool::Controller#reuse' from /home/samuel/.gem/ruby/3.4.0/gems/async-pool-0.10.3/lib/async/pool/controller.rb:154:in 'Async::Pool::Controller#release' from /home/samuel/Developer/socketry/async/external/async-http/lib/async/http/protocol/http1/client.rb:29:in 'Async::HTTP::Protocol::HTTP1::Client#closed' from /home/samuel/.gem/ruby/3.4.0/gems/protocol-http1-0.34.0/lib/protocol/http1/connection.rb:725:in 'Protocol::HTTP1::Connection#close!' from /home/samuel/.gem/ruby/3.4.0/gems/protocol-http1-0.34.0/lib/protocol/http1/connection.rb:776:in 'Protocol::HTTP1::Connection#receive_end_stream!' from /home/samuel/.gem/ruby/3.4.0/gems/protocol-http1-0.34.0/lib/protocol/http1/body/fixed.rb:63:in 'Protocol::HTTP1::Body::Fixed#read' from /home/samuel/.gem/ruby/3.4.0/gems/protocol-http-0.51.0/lib/protocol/http/body/readable.rb:96:in 'Protocol::HTTP::Body::Readable#each' from /home/samuel/.gem/ruby/3.4.0/gems/protocol-http-0.51.0/lib/protocol/http/body/buffered.rb:40:in 'Protocol::HTTP::Body::Buffered.read' from /home/samuel/.gem/ruby/3.4.0/gems/protocol-http-0.51.0/lib/protocol/http/body/readable.rb:157:in 'Protocol::HTTP::Body::Readable#finish' from /home/samuel/.gem/ruby/3.4.0/gems/protocol-http-0.51.0/lib/protocol/http/body/reader.rb:41:in 'Protocol::HTTP::Body::Reader#finish' from /home/samuel/Developer/socketry/async/external/async-http/fixtures/async/http/a_protocol.rb:586:in 'block (6 levels) in <module:HTTP>' from /home/samuel/Developer/socketry/async/external/async-http/fixtures/async/http/a_protocol.rb:584:in 'Kernel#loop' from /home/samuel/Developer/socketry/async/external/async-http/fixtures/async/http/a_protocol.rb:584:in 'block (5 levels) in <module:HTTP>' from /home/samuel/Developer/socketry/async/lib/async/task.rb:205:in 'block in Async::Task#run' from /home/samuel/Developer/socketry/async/lib/async/task.rb:443:in 'block in Async::Task#schedule' 1m warn: Async::HTTP::Client: running example [oid=0x3e28] [ec=0x3e30] [pid=47323] [2025-07-13 23:16:04 +1200] | Waiting for Async::HTTP::Protocol::HTTP10 pool to drain: #<Async::Pool::Controller(20/∞) 1/1*/84663;1/1*/84662;0/1*/15;1/1*/84661;1/1*/84662;1/1*/84661;1/1*/84661;1/1*/84660;1/1*/84661;1/1*/84660;1/1*/84660;0/1*/26;1/1*/84536;1/1*/84659;1/1*/84659;1/1*/84659;0/1*/32;1/1*/84658;1/1*/84658;1/1*/84657> 

After this, the cancellation is ignored, and the test hangs/fails.

For now, let's use Tempfile in a way that doesn't cause finalizers to run.

Types of Changes

• Maintenance.

Contribution

• I added tests for my changes.
• I tested my changes locally.
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