Gem.open_file_with_flock

# File tmp/rubies/ruby-3.4.1/lib/rubygems.rb, line 811
def self.open_file_with_flock(path, &block)
  # read-write mode is used rather than read-only in order to support NFS
  mode = IO::RDWR | IO::APPEND | IO::CREAT | IO::BINARY
  mode |= IO::SHARE_DELETE if IO.const_defined?(:SHARE_DELETE)

  File.open(path, mode) do |io|
    begin
      io.flock(File::LOCK_EX)
    rescue Errno::ENOSYS, Errno::ENOTSUP
    end
    yield io
  end
end