Trying to get multiple threads working with March Hare

example.rb

require 'march_hare'

connection = MarchHare.connect(:host => 'localhost', :thread_pool_size => 8)
channel = connection.create_channel
channel.prefetch = 10

exchange = channel.exchange('test', :type => :direct)

queue = channel.queue('hello.world')
queue.bind(exchange, :routing_key => 'xyz')
queue.purge

consumer = queue.subscribe(:ack => true, :blocking => false, :executor => ::MarchHare::ThreadPools.dynamically_growing) do |headers, msg|
  puts msg

  x = Random.rand * 3
  puts "   working for #{x}s"
  sleep(x)

  headers.ack
end

100.times do |i|
  exchange.publish("hello world! #{i}", :routing_key => 'xyz')
end

# make sure all messages are processed before we cancel
# to avoid confusing exceptions from the [already shutdown] executor. MK.
sleep 100.0
consumer.cancel

puts "Disconnecting now..."

at_exit do
  channel.close
  connection.close
end

threads.rb

require 'march_hare'

connection = MarchHare.connect(:host => 'localhost')

10.times do
  channel = connection.create_channel
  channel.prefetch = 1
  exchange = channel.exchange('test', :type => :direct)
  queue = channel.queue('hello.world')
  queue.bind(exchange, :routing_key => 'xyz')
  queue.subscribe(:ack => true, :blocking => false) do |headers, msg|
    puts msg
  
    x = Random.rand * 3
    puts "   working for #{x}s"
    sleep(x)
  
    headers.ack
  end
end