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# Asynchronous I/O Operations
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High-performance asynchronous I/O operations for external system integration with configurable parallelism, timeouts, and result ordering.
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## Imports
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```scala
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import org.apache.flink.streaming.api.scala._
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import org.apache.flink.streaming.api.scala.async.{AsyncFunction, AsyncCollector}
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import java.util.concurrent.TimeUnit
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```
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## AsyncDataStream Operations
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```scala { .api }
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object AsyncDataStream {
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  def unorderedWait[IN, OUT: TypeInformation](
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    input: DataStream[IN],
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    asyncFunction: AsyncFunction[IN, OUT],
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    timeout: Long,
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    timeUnit: TimeUnit
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  ): DataStream[OUT]
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  def orderedWait[IN, OUT: TypeInformation](
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    input: DataStream[IN],
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    asyncFunction: AsyncFunction[IN, OUT],
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    timeout: Long,
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    timeUnit: TimeUnit
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  ): DataStream[OUT]
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}
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```
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## AsyncFunction Interface
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```scala { .api }
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trait AsyncFunction[IN, OUT] {
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  def asyncInvoke(input: IN, collector: AsyncCollector[OUT]): Unit
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}
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trait AsyncCollector[OUT] {
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  def collect(result: Iterable[OUT]): Unit
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  def collect(throwable: Throwable): Unit
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}
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```
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Enables non-blocking I/O operations for database lookups, REST API calls, and other external system interactions.