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diff --git a/reactive/kotlinx-coroutines-reactor/src/Flux.kt b/reactive/kotlinx-coroutines-reactor/src/Flux.kt
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+
+/*
+ * Copyright 2016-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+@file:Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
+
+package kotlinx.coroutines.reactor
+
+import kotlinx.coroutines.*
+import kotlinx.coroutines.channels.*
+import kotlinx.coroutines.reactive.*
+import org.reactivestreams.Publisher
+import reactor.core.CoreSubscriber
+import reactor.core.publisher.*
+import kotlin.coroutines.*
+import kotlin.internal.LowPriorityInOverloadResolution
+
+/**
+ * Creates cold reactive [Flux] that runs a given [block] in a coroutine.
+ * Every time the returned flux is subscribed, it starts a new coroutine in the specified [context].
+ * Coroutine emits items with `send`. Unsubscribing cancels running coroutine.
+ *
+ * Coroutine context can be specified with [context] argument.
+ * If the context does not have any dispatcher nor any other [ContinuationInterceptor], then [Dispatchers.Default] is used.
+ *
+ * Invocations of `send` are suspended appropriately when subscribers apply back-pressure and to ensure that
+ * `onNext` is not invoked concurrently.
+ *
+ * | **Coroutine action**                         | **Signal to subscriber**
+ * | -------------------------------------------- | ------------------------
+ * | `send`                                       | `onNext`
+ * | Normal completion or `close` without cause   | `onComplete`
+ * | Failure with exception or `close` with cause | `onError`
+ *
+ * Method throws [IllegalArgumentException] if provided [context] contains a [Job] instance.
+ *
+ * **Note: This is an experimental api.** Behaviour of publishers that work as children in a parent scope with respect
+ *        to cancellation and error handling may change in the future.
+ */
+@ExperimentalCoroutinesApi
+public fun <T> flux(
+    context: CoroutineContext = EmptyCoroutineContext,
+    @BuilderInference block: suspend ProducerScope<T>.() -> Unit
+): Flux<T> {
+    require(context[Job] === null) { "Flux context cannot contain job in it." +
+        "Its lifecycle should be managed via Disposable handle. Had $context" }
+    return Flux.from(reactorPublish(GlobalScope, context, block))
+}
+
+@Deprecated(
+    message = "CoroutineScope.flux is deprecated in favour of top-level flux",
+    level = DeprecationLevel.WARNING,
+    replaceWith = ReplaceWith("flux(context, block)")
+) // Since 1.3.0, will be error in 1.3.1 and hidden in 1.4.0. Binary compatibility with Spring
+@LowPriorityInOverloadResolution
+public fun <T> CoroutineScope.flux(
+    context: CoroutineContext = EmptyCoroutineContext,
+    @BuilderInference block: suspend ProducerScope<T>.() -> Unit
+): Flux<T> =
+    Flux.from(reactorPublish(this, context, block))
+
+private fun <T> reactorPublish(
+    scope: CoroutineScope,
+    context: CoroutineContext = EmptyCoroutineContext,
+    @BuilderInference block: suspend ProducerScope<T>.() -> Unit
+): Publisher<T> = Publisher { subscriber ->
+    // specification requires NPE on null subscriber
+    if (subscriber == null) throw NullPointerException("Subscriber cannot be null")
+    require(subscriber is CoreSubscriber) { "Subscriber is not an instance of CoreSubscriber, context can not be extracted." }
+    val currentContext = subscriber.currentContext()
+    val reactorContext = (context[ReactorContext]?.context?.putAll(currentContext) ?: currentContext).asCoroutineContext()
+    val newContext = scope.newCoroutineContext(context + reactorContext)
+    val coroutine = PublisherCoroutine(newContext, subscriber)
+    subscriber.onSubscribe(coroutine) // do it first (before starting coroutine), to avoid unnecessary suspensions
+    coroutine.start(CoroutineStart.DEFAULT, coroutine, block)
+}
+\ No newline at end of file