Explain how await() should not be used with an OTP behaviour

Author: alco

lib/elixir/lib/task.ex

@@ -307,6 +307,12 @@ defmodule Task do
  This function can only be called once for any given task. If you want
  to be able to check multiple times if a long-running task has finished
  its computation, use `yield/2` instead.
+
+ ## Compatibility with OTP behaviours
+
+ It is not recommended to `await` a long-running task inside an OTP
+ behaviour such as `GenServer`. Instead, you should match on the message
+ coming from a task inside your `handle_info` callback.
  """
  @spec await(t, timeout) :: term | no_return
  def await(task, timeout \\ 5000)