[docs] The document is outdated

[resetsix]

Hello, I am a user of Recouse/EventSource, and I would like to express my gratitude for your hard work on EventSource.

I installed the dependency at version v0.1.4, and when I updated the dependencies today, I suddenly encountered an error related to the cancel parameter. I found out that the API parameters were updated in the new version (v0.1.5), but there were no related explanations. I feel that others might encounter this issue as well. Therefore, I am willing to submit a PR to explain this situation.

[Recouse]

Yes, there have been major changes across versions. Since these are all unstable releases, the APIs may change with each update. I'll work on documenting the changes better and will review your PR

[resetsix]

Thank you, if there is anything wrong, you can correct it at any time