class MessagePack::Factory::Pool::MemberPool

def with
  member = @members.pop || @new_member.call
  begin
    yield member
  ensure
    # If the pool is already full, we simply drop the extra member.
    # This is because contrary to a connection pool, creating an extra instance
    # is extremely unlikely to cause some kind of resource exhaustion.
    #
    # We could cycle the members (keep the newer one) but first It's more work and second
    # the older member might have been created pre-fork, so it might be at least partially
    # in shared memory.
    if member && @members.size < @size
      member.reset
      @members << member
    end
  end
end