Another action available on Flow is onStart(). This is called before the Flow starts emitting objects. You are passed a FlowCollector, which is the same object that is passed into the lambda expression of the flow() function. FlowCollector has the emit() function, and whatever your onStart() code emits is emitted by the Flow before any of the "real" entries.

So, in this case, in addition to ten random numbers from 0-100, we start the Flow with 1337.

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A Conflated Channel A Fixed-Buffer Channel A Parallel Coroutine Sample A Sequential Coroutine Sample A Simple Channel A Simple Coroutine Sample A Simple Flow A Simple SharedFlow A Simple StateFlow A Zero-Buffer Channel async() BroadcastChannel cancelAndJoin() Canceling a Job Canceling a Parent Cancels Its Children Canceling and Cooperation catch() Channel and receive() Channels and Fan-out combine() Operator Contexts and Jobs Cooperation by Checking isActive Cooperation by Yielding debounce() Operator distinctUntilChanged() Operator distinctUntilChangedBy() Operator drop() Operator dropWhile() Operator filter() Operator filterIsInstance() Operator filterNot() Operator filterNotNull() Operator first() and Flow flattenConcat() Operator flattenMerge() Operator Flow Actions Flow onStart() flowOf() flowOn() Flows and Exceptions fold() Operator Hot Channels Via offer() invokeOnCompletion() Jobs and Parents Jobs Cancel When They Crash join() Lazy Coroutines map() Operator mapLatest() Operator mapNotNull() Operator Massively Parallel Coroutines MutableSharedFlow Replay Option Non-Cancellable Coroutines Parent Jobs Cancel When a Child Crashes promise() retry() retryWhen() runBlocking() sample() Operator scan() Operator single() and singleOrNull() Starting Lazy Coroutines StateFlow and Content Equality suspend Functions and Flows Suspending main() take() Operator takeWhile() Operator The Channel() Function TimeoutCancellationException Timeouts toList() and toSet() toList() for Channel withIndex() Operator withTimeoutOrNull() zip() Operator
A Simple Flow A Simple SharedFlow A Simple StateFlow catch() combine() Operator debounce() Operator distinctUntilChanged() Operator distinctUntilChangedBy() Operator drop() Operator dropWhile() Operator filter() Operator filterIsInstance() Operator filterNot() Operator filterNotNull() Operator first() and Flow flattenConcat() Operator flattenMerge() Operator Flow Actions Flow onStart() flowOf() flowOn() Flows and Exceptions fold() Operator map() Operator mapLatest() Operator mapNotNull() Operator MutableSharedFlow Replay Option retry() retryWhen() sample() Operator scan() Operator single() and singleOrNull() StateFlow and Content Equality suspend Functions and Flows take() Operator takeWhile() Operator toList() and toSet() withIndex() Operator zip() Operator
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