[Twisted-Python] Return only when value/handle is available

[exarkun at twistedmatrix.com]

On 05:52 pm, vikas.c.kumar at oracle.com wrote:
>Hi Jonas,
>
>This is nice.
>But still we are retrying it repeatedly at regular interval(10). Can't 
>we get the notified asynchronously as and when handle is available.

You tell us.  What's a handle?  Where do you get it from?  Does that 
system produce an event when it is ready?

Jean-Paul