gevent携程，自动切换（IO）

import gevent

def foo():
    print('Running in foo')
    gevent.sleep(2)
    print('Explicit context switch to foo again')
def bar():
    print('Explicit精确的 context内容 to bar')
    gevent.sleep(1)
    print('Implicit context switch back to bar')
def func3():
    print("running func3 ")
    gevent.sleep(0)
    print("running func3  again ")


gevent.joinall([
    gevent.spawn(foo), #生成，
    gevent.spawn(bar),
    gevent.spawn(func3),
])


#=======================

Running in foo
Explicit精确的 context内容 to bar
running func3
running func3 again
Implicit context switch back to bar
Explicit context switch to foo again