Add ReconnectInterval option in ServerSentEventsServiceOptions

[Eli-Black-Work]

In our project, we want our ServerSentEventsService to be started with a different reconnect interval than the default.

Currently, this seems a bit difficult to do, because ChangeReconnectIntervalAsync() is async, so it can't be awaited in the ServerSentEventsService constructor.

Could you please add a ReconnectInterval field to ServerSentEventsServiceOptions, so that the reconnect interval could easily be set when configuring the service?

Thanks :)

[tpeczek]

This change makes perfect sens and won't be problematic, so I will take care of adding this.

[Eli-Black-Work]

Yay! Thank you :)

[tpeczek]

You're welcome