Quick demo of the problem of resetting Ruby STDLIB's Coverage mid-way

cov.rb

# On "ruby 2.0.0p195 (2013-05-14 revision 40734) [x86_64-linux]", but should be the same on all 1.9+
require 'coverage'
Coverage.start
require './foo'
puts Coverage.result
# {"foo.rb"=>[1, 1, 0, nil, nil, 1, 0, nil, nil]}

Coverage.start
Foo.new.bar
puts Coverage.result
# {"foo.rb"=>[]}

foo.rb

class Foo
  def bar
    :bar
  end

  def baz
    :baz
  end
end