User Consent - Allow manual sending of events

### Problem Statement

Currently sending of events seems to be fully automatic.
I want to ask my users for consent before sending the crash report.

### Solution Brainstorm

I'm interested in the SDKs for Java, iOS & macOS.

[Crashlytics]() has the following methods:

* `setCrashlyticsCollectionEnabled(boolean enabled)` to enable automatic sending of events
* `checkForUnsentReports()` to check if I should show a promt asking the user
* `sendUnsentReports()` to send the report (after the user aggreed to)
* `deleteUnsentReports()` to delete them if the user does not want to send the report