Update multiple client example by adding a call to flush

[rhcarvalho]

We need a clear example of how to use multiple clients and how to properly Flush events upon program termination.

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See #153 (comment)

IMHO User only knows about Sentry.flush and worst case SentryClient.flush if they are working with the client directly (outside the SDK.init/Hub)

I wish this was simpler too.

If there is only ever one client, then sentry.Flush does the job.
If new clients are created, then more Flush calls need to be sprinkled around for correctness. We need a clear example for this usage.

[rhcarvalho]

Oh, it's already there! https://github.com/getsentry/sentry-go/blob/master/example/multiclient/main.go

Good job @kamilogorek!

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Need to update the example to call Flush.

[kamilogorek]

Thanks, tried my best :)

[github-actions]

This issue has gone three weeks without activity. In another week, I will close it.

But! If you comment or otherwise update it, I will reset the clock, and if you label it Status: Backlog or Status: In Progress, I will leave it alone ... forever!

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"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀