While formal models of concurrency tend to focus on synchronous communication, asynchronous communication is relevant in practice. In this paper, we will discuss asynchronous communication in the context of session-based concurrency, the model of computation in which session types specify the structure of the two-party protocols implemented by the channels of a communicating process. We overview recent work on addressing the challenge of ensuring the deadlock-freedom property for message-passing processes that communicate asynchronously in cyclic process networks governed by session types. We offer a gradual presentation of three typed process frameworks and outline how they may be used to guarantee deadlock freedom for a concurrent functional language with sessions.

翻译：尽管形式化并发模型通常侧重于同步通信，但异步通信在实践中同样具有重要意义。本文将在会话式并发性的背景下讨论异步通信——这是一种计算模型，其中会话类型规定了由通信进程通道实现的双方协议结构。我们综述了近期在确保异步消息传递进程无死锁性方面的研究进展，这些进程在会话类型控制的循环进程网络中通过异步通信进行交互。本文逐步介绍了三种类型化进程框架，并概述了如何利用这些框架为支持会话机制的并发函数式语言提供无死锁保证。