✨ Add a system for creating task chains

This will make it easier to use the asynchronous coordinator.

cloud-tasks/src/main/java/cloud/commandframework/tasks/TaskSynchronizer.java

@@ -0,0 +1,77 @@
+//
+// MIT License
+//
+// Copyright (c) 2020 Alexander Söderberg & Contributors
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+package cloud.commandframework.tasks;
+
+import org.checkerframework.checker.nullness.qual.NonNull;
+
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * Utility responsible for synchronizing {@link TaskRecipeStep task recipe steps}
+ */
+public interface TaskSynchronizer {
+
+    /**
+     * Accept input into the consumer synchronously
+     *
+     * @param input    Input to pass to the consumer
+     * @param consumer Consumer of the input
+     * @param <I>      Input type
+     * @return Future that completes when the consumer is done
+     */
+    <I> CompletableFuture<Void> runSynchronous(@NonNull I input, @NonNull TaskConsumer<I> consumer);
+
+    /**
+     * Produce output from accepted input synchronously
+     *
+     * @param input    Input to pass to the function
+     * @param function Function that produces the output
+     * @param <I>      Input type
+     * @param <O>      Output type
+     * @return Future that completes with the output
+     */
+    <I, O> CompletableFuture<O> runSynchronous(@NonNull I input, @NonNull TaskFunction<I, O> function);
+
+    /**
+     * Accept input into the consumer asynchronously
+     *
+     * @param input    Input to pass to the consumer
+     * @param consumer Consumer of the input
+     * @param <I>      Input type
+     * @return Future that completes when the consumer is done
+     */
+    <I> CompletableFuture<Void> runAsynchronous(@NonNull I input, @NonNull TaskConsumer<I> consumer);
+
+    /**
+     * Produce output from accepted input asynchronously
+     *
+     * @param input    Input to pass to the function
+     * @param function Function that produces the output
+     * @param <I>      Input type
+     * @param <O>      Output type
+     * @return Future that completes with the output
+     */
+    <I, O> CompletableFuture<O> runAsynchronous(@NonNull I input, @NonNull TaskFunction<I, O> function);
+
+}