NewStream creates a new stream against the provided response writer.

Pumped returns a channel that will be closed the next time the input pump sends.

Tick triggers any open SSE streams to tick by replacing and closing the `nextTick` trigger channel.

WriteEvent does the actual work of formatting an SSE compliant message sending it over the provided ResponseWriter and flushing.

WritePreamble prepares this http connection for streaming using Server Sent Events.

Event is the packet of data that gets sent over the wire to a connected client.

Eventable represents an object that can be converted to an SSE compatible event.

Stream represents an output stream that data can be written to.