greenlet实现协程

#greenlet
 1 import time
 from greenlet import greenlet
 # greenlet可以实现一个自行调度的微线程
 def work1():
     while True:
         print("正在执行work1（）")
         time.sleep(0.5)#模拟阻塞
         # 如果遇到阻塞的情况下，切换到第二个任务
         g2.switch()

 def work2():
     while True:
         print("正在执行work2（）")
         time.sleep(0.5)
         # 切换到第一个任务
         g1.switch()

 if __name__ == '__main__':
     # 创建greenlet的对象    greenlet（函数名）
     g1 = greenlet(work1)
     g2 = greenlet(work2)
     g1.switch()