Feature request: add client side support

[welkeyever]

Is your feature request related to a problem? Please describe.
There is no SSE client side support from hertz.

Describe the solution you'd like
Maybe implement it by wrapping hertz-client.

Describe alternatives you've considered
may refer here: https://github.com/r3labs/sse.

[ViolaPioggia]

I want to try