What causes a `scheduledTimer` to function correctly if it is set up outside a block but not inside a block?

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The scheduledTimer function relies on the run loop of the application to function correctly. If a timer is set up outside a block, it is added to the run loop and scheduled to execute at the specified interval. However, if a timer is set up inside a block, it may not be added to the run loop immediately and may not execute as expected. This is because the block may be executed on a different thread or at a later time, interrupting the normal flow of the run loop. To ensure a timer functions correctly, it should be set up outside any blocks and added to the run loop immediately.