pingInterval property Null safety
The interval between ping signals.
A ping message is sent every pingInterval, starting at the first
pingInterval after a new value has been assigned or a pong message has
been received. If a ping message is not answered by a pong message from the
WebSocket is assumed disconnected and the connection is closed
with a WebSocketStatus.goingAway close code. When a ping signal is sent,
the pong message must be received within pingInterval.
There are never two outstanding pings at any given time, and the next ping timer starts when the pong is received.
Set the pingInterval to
null to disable sending ping messages.
The default value is