Add some pending specs for the Listener class.
user
```ruby
# frozen_string_literal: true

require 'spec_helper'

describe Que::Listener do
  it "should return messages to the locker in bulk by type"

  it "should pre-process new_job messages"

  it "should be resilient to messages that aren't invalid JSON"

  it "when unlistening should not leave any residual messages"
end
```
assistant