class Bundler::Installer

def can_install_in_parallel?
  if Bundler.rubygems.provides?(">= 2.1.0")
    true
  else
    Bundler.ui.warn "Rubygems #{Gem::VERSION} is not threadsafe, so your "\
      "gems will be installed one at a time. Upgrade to Rubygems 2.1.0 " \
      "or higher to enable parallel gem installation."
    false
  end
end