Add support for persistent connections

[mkonecny]

APNS appears to close the connection after each message (or group of messages). From the APNS documentation:

Keep your connections with APNs open across multiple notifications; don’t repeatedly open and close connections. APNs treats rapid connection and disconnection as a denial-of-service attack. You should leave a connection open unless you know it will be idle for an extended period of time—for example, if you only send notifications to your users once a day it is ok to use a new connection each day.

In the worst case scenario, I could see Apple revoking your push certificate should your volume increase to the point they consider it a DDOS attack.

[ghost]

+1