class EventMachine::MySQL

def query(sql, &blk)
  f = Fiber.current
  # TODO: blk case does not work. Hmm?
  cb = Proc.new { |r| f.resume(r) }
  eb = Proc.new { |r| f.resume(r) }
  @connection.execute(sql, cb, eb)
  result = Fiber.yield
  raise result if Mysql::Error == result.class
  result
end