Test EventSource text/event-stream parsing. Should print a series of PASS messages followed by DONE.

PASS: got open event
PASS: received event with two newlines
PASS: received event with data "simple"
PASS: received event with data spanning multiple lines
PASS: received event and lastEventId is "1"
PASS: received event and lastEventId is still "1"
PASS: received event and lastEventId has been cleared
PASS: got open event from server
PASS: received event and the event name has been reset
PASS: received event with data that contains a colon
DONE