fix send trait typo

content/concurrency-patterns.md

@@ -35,7 +35,7 @@ This post is specifically about sharing mutable state in IO-bound applications.
 
 The most common way to achieve concurrency in an async runtime is to spawn new tasks to handle IO events. Task is a primitive provided by async runtimes that represents a unit of work. As IO events unblock this unit of work, it can then be scheduled on the same thread or another to run concurrently with other tasks.
 
-There's a price to pay for that convenience; any `Future` that task is meant to execute must be `'static` and possibly `'Send`. For the latter, it's only a requirement if the task can be scheduled in different threads. This can be prevented by using constructs like `tokio::task::LocalSet`; and although it can be a bit unwieldy, it will get rid of the `'Send` requirement. However, `'static` is a much harder requirement to get rid of.
+There's a price to pay for that convenience; any `Future` that task is meant to execute must be `'static` and possibly `Send`. For the latter, it's only a requirement if the task can be scheduled in different threads. This can be prevented by using constructs like `tokio::task::LocalSet`; and although it can be a bit unwieldy, it will get rid of the `Send` requirement. However, `'static` is a much harder requirement to get rid of.
 
 `'static` is a requirement because the spawned `Future` can be run at any later time, even outliving the scope of the block that originally spawned it. There are two ways to meet this requirement and have a mutable state: either by using a structure with internal mutability to store state or by having single ownership of the different pieces of state in different tasks and coordinating between them using channels.