Add Accept header by default

[EmmaSimon]

It looks like the listener is only able to consume data formatted as text/event-stream, since that's the case, is there a good reason not to automatically set the Accept header to that mimetype, since nothing else is actually accepted?

[Imgkl]

First of all, Thanks to @pratikbaid3 for this package. This issue led me to create my own package with better error handling and reconnection logic.

Check it out, EventFlux.