Code

from pprint import pprint
from time import sleep, time

from twisted.internet import defer, reactor


def stop():
    if not reactor.getDelayedCalls():
        reactor.stop()
    reactor.callLater(0.1, stop)


def locked_print(msg):
    sleep(0.01)
    pprint(msg + ', Time: {}'.format(time()))


def print_later(delay, msg):
    dfd = defer.Deferred()
    dfd.addCallback(locked_print)
    reactor.callLater(delay, dfd.callback, msg)


if __name__ == '__main__':
    total = 10
    for idx in range(total):
        print_later(0.1, 'Delay: 0.1, Index: {}'.format(idx))
    for idx in range(total):
        print_later(0, 'Delay: 0, Index: {}'.format(idx))
        sleep(0.1)
    reactor.callLater(0.1, stop)
    reactor.run()

Results

'Delay: 0, Index: 0, Time: 1426595265.61'
'Delay: 0.1, Index: 0, Time: 1426595265.62'
'Delay: 0.1, Index: 1, Time: 1426595265.63'
'Delay: 0.1, Index: 2, Time: 1426595265.64'
'Delay: 0.1, Index: 3, Time: 1426595265.65'
'Delay: 0.1, Index: 4, Time: 1426595265.66'
'Delay: 0.1, Index: 5, Time: 1426595265.67'
'Delay: 0.1, Index: 6, Time: 1426595265.68'
'Delay: 0.1, Index: 7, Time: 1426595265.69'
'Delay: 0.1, Index: 8, Time: 1426595265.7'
'Delay: 0.1, Index: 9, Time: 1426595265.71'
'Delay: 0, Index: 1, Time: 1426595265.72'
'Delay: 0, Index: 2, Time: 1426595265.73'
'Delay: 0, Index: 3, Time: 1426595265.74'
'Delay: 0, Index: 4, Time: 1426595265.75'
'Delay: 0, Index: 5, Time: 1426595265.76'
'Delay: 0, Index: 6, Time: 1426595265.77'
'Delay: 0, Index: 7, Time: 1426595265.78'
'Delay: 0, Index: 8, Time: 1426595265.8'
'Delay: 0, Index: 9, Time: 1426595265.81'