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Coroutines support libraries for Kotlin
/*
* Copyright 2016-2023 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
*/
package kotlinx.coroutines
/**
* The [CoroutineDispatcher] that is designed for offloading blocking IO tasks to a shared pool of threads.
* Additional threads in this pool are created on demand.
* Default IO pool size is `64`; on JVM it can be configured using JVM-specific mechanisms,
* please refer to `Dispatchers.IO` documentation on JVM platform.
*
* ### Elasticity for limited parallelism
*
* `Dispatchers.IO` has a unique property of elasticity: its views
* obtained with [CoroutineDispatcher.limitedParallelism] are
* not restricted by the `Dispatchers.IO` parallelism. Conceptually, there is
* a dispatcher backed by an unlimited pool of threads, and both `Dispatchers.IO`
* and views of `Dispatchers.IO` are actually views of that dispatcher. In practice
* this means that, despite not abiding by `Dispatchers.IO`'s parallelism
* restrictions, its views share threads and resources with it.
*
* In the following example
* ```
* // 100 threads for MySQL connection
* val myMysqlDbDispatcher = Dispatchers.IO.limitedParallelism(100)
* // 60 threads for MongoDB connection
* val myMongoDbDispatcher = Dispatchers.IO.limitedParallelism(60)
* ```
* the system may have up to `64 + 100 + 60` threads dedicated to blocking tasks during peak loads,
* but during its steady state there is only a small number of threads shared
* among `Dispatchers.IO`, `myMysqlDbDispatcher` and `myMongoDbDispatcher`
*/
@Suppress("EXTENSION_SHADOWED_BY_MEMBER")
public expect val Dispatchers.IO: CoroutineDispatcher