Optional
onMessage: ((msg: EventSourceMessage) => void)A function that will be called on each message.
Optional
onId: ((id: string) => void)A function that will be called on each id
field.
Optional
onRetry: ((retry: number) => void)A function that will be called on each retry
field.
A function that should be called for each incoming line buffer.
Optional
flush: boolean
Parses line buffers into EventSourceMessages.