Bug 1918144 - Document submitting Glean events in "real-time"

[travis79]

This adds some more specific documentation about Glean's ability to submit events in "real-time" (sending, not analyzing) by way of using the maximum events per ping parameter to cause Glean to send an events ping for every event recorded.

This will be augmented later once I've gotten a chance to run some experiments and measure the impacts with real data.

[chutten]

The doc's a little slim on reasons why someone might choose to configure a Glean SDK in this way. Is this intentional, or should we write a sentence like "this, in ideal network and ingestion circumstances, can allow data to arrive within seconds-to-minutes of being recorded"

[travis79]

The doc's a little slim on reasons why someone might choose to configure a Glean SDK in this way. Is this intentional, or should we write a sentence like "this, in ideal network and ingestion circumstances, can allow data to arrive within seconds-to-minutes of being recorded"

It's light on marketing details because I still have some work and measurement of impacts that I'd like to do to complete this documentation. I'd like to be able to back up any claims and potential impacts with real data. This'll be tracked in Bug 1918149