Launch another Ruby Interpreter when IRB is started

[neko314]

from https://github.com/ruby/irb/pull/254#issuecomment-871698900

Separation running and input interpreters sounds good. But I know it's never easy.

At first I can do is creating issue so I do.

Expected benefits

• Running something(ex compiling) to check the code on background does not effect the input interpreter
• Reduce requre
• maybe something more...

[st0012]

I did a bit debugging with ruby/debug:

$ ruby -Ilib -rnet/http -rdebug -e "debugger(do: 'trace call') ;;  puts Net::HTTP.get(URI.parse('https://raw.githubusercontent.com/ruby/debug/master/.gitignore'))"

And I think it hangs at

DEBUGGER (trace/call) #th:1 #depth:19>                  IO#wait_readable at /Users/st0012/.rbenv/versions/3.1.0/lib/ruby/3.1.0/net/protocol.rb:219

More traces:

# ...
DEBUGGER (trace/call) #th:1 #depth:20<                   OpenSSL::SSL::SSLSocket#sysread_nonblock #=> :wait_readable at /Users/st0012/.rbenv/versions/3.1.0/lib/ruby/3.1.0/openssl/buffering.rb:214
DEBUGGER (trace/call) #th:1 #depth:19<                   OpenSSL::Buffering#read_nonblock #=> :wait_readable at /Users/st0012/.rbenv/versions/3.1.0/lib/ruby/3.1.0/openssl/buffering.rb:214
DEBUGGER (trace/call) #th:1 #depth:19>                  Module#=== at /Users/st0012/.rbenv/versions/3.1.0/lib/ruby/3.1.0/net/protocol.rb:213
DEBUGGER (trace/call) #th:1 #depth:19<                  Module#=== #=> false at /Users/st0012/.rbenv/versions/3.1.0/lib/ruby/3.1.0/net/protocol.rb:213
DEBUGGER (trace/call) #th:1 #depth:19>                  Symbol#=== at /Users/st0012/.rbenv/versions/3.1.0/lib/ruby/3.1.0/net/protocol.rb:218
DEBUGGER (trace/call) #th:1 #depth:19<                  Symbol#=== #=> true at /Users/st0012/.rbenv/versions/3.1.0/lib/ruby/3.1.0/net/protocol.rb:218
DEBUGGER (trace/call) #th:1 #depth:19>                  OpenSSL::SSL::SSLSocket#io at /Users/st0012/.rbenv/versions/3.1.0/lib/ruby/3.1.0/net/protocol.rb:219
DEBUGGER (trace/call) #th:1 #depth:19<                  OpenSSL::SSL::SSLSocket#io #=> #<Socket:fd 11> at /Users/st0012/.rbenv/versions/3.1.0/lib/ruby/3.1.0/net/protocol.rb:219
DEBUGGER (trace/call) #th:1 #depth:19>                  IO#wait_readable at /Users/st0012/.rbenv/versions/3.1.0/lib/ruby/3.1.0/net/protocol.rb:219