Update Readme with new imports

Readme.md

@@ -17,16 +17,29 @@ requires "asynctest >= 0.4.3 & < 0.5.0"
 Usage
 -----
 
-Simply replace `import unittest` with `import asynctest`, and you can await
+Replace `import unittest` with one of the following imports, and you can await
 asynchronous calls in tests, setup and teardown.
 
+When you use Nim's standard library only ([asyncdispatch][4] and [unittest][1]):
+```nim
+import asynctest/asyncdispatch/unittest
+```
+
+When you use [chronos][5] or [unittest2][3], pick the import that matches your
+choices:
+
+```nim
+import asynctest/asyncdispatch/unittest2  # standard async and unittest2
+import asynctest/chronos/unittest         # chronos and standard unittest
+import asynctest/chronos/unittest2        # chronos and unittest2
+```
+
 Example
 -------
 
 ```nim
 
-import asynctest
-import asyncdispatch # alternatively: import chronos
+import asynctest/asyncdispatch/unittest
 
 proc someAsyncProc {.async.} =
   # perform some async operations using await
@@ -47,17 +60,6 @@ suite "test async proc":
 
 ```
 
-setupAll and teardownAll
-------------------------
-
-The `setup` and `teardown` code runs before and after every test, just like the
-standard [unittest][1] module. In addition we provide `setupAll` and
-`teardownAll`. The `setupAll` code runs once before all tests in the suite, and
-the `teardownAll` runs once after all tests in the suite. Use these only as a
-last resort when setting up the test environment is very costly. Be careful that
-the tests do not modify the environment that you set up, lest you introduce
-dependencies between tests.
-
 check eventually
 ----------------
 
@@ -78,12 +80,20 @@ check eventually x == 42
 await future
 ```
 
-Unittest2
----------
+setupAll and teardownAll
+------------------------
+
+The `setup` and `teardown` code runs before and after every test, just like the
+standard [unittest][1] module. In addition we provide `setupAll` and
+`teardownAll`. The `setupAll` code runs once before all tests in the suite, and
+the `teardownAll` runs once after all tests in the suite. Use these only as a
+last resort when setting up the test environment is very costly. Be careful that
+the tests do not modify the environment that you set up, lest you introduce
+dependencies between tests.
 
-The [unittest2][3] package is supported. Make sure that you
-`import asynctest/unittest2` instead of the normal import.
 
 [1]: https://nim-lang.org/docs/unittest.html
 [2]: https://github.com/nim-lang/nimble
 [3]: https://github.com/status-im/nim-unittest2
+[4]: https://nim-lang.org/docs/asyncdispatch.html
+[5]: https://github.com/status-im/nim-chronos/