cpython-uasyncio: Add StreamWriter with awrite() & aclose().

cpython-uasyncio/metadata.txt

@@ -1,3 +1,3 @@
 srctype = cpython-backport
 type = module
-version = 0.1
+version = 0.2

cpython-uasyncio/setup.py

@@ -6,7 +6,7 @@ from setuptools import setup
 
 
 setup(name='micropython-cpython-uasyncio',
-      version='0.1',
+      version='0.2',
       description='MicroPython module uasyncio ported to CPython',
       long_description='This is MicroPython compatibility module, allowing applications using\nMicroPython-specific features to run on CPython.\n',
       url='https://github.com/micropython/micropython/issues/405',

cpython-uasyncio/uasyncio.py

@@ -78,3 +78,22 @@ class Task(OrgTask):
 
 
 asyncio.tasks.Task = Task
+
+
+OrgStreamWriter = StreamWriter
+
+class StreamWriter(OrgStreamWriter):
+
+    def awrite(self, data):
+        if isinstance(data, str):
+            data = data.encode("utf-8")
+        self.write(data)
+        yield from self.drain()
+
+    def aclose(self):
+        self.close()
+        return
+        yield
+
+
+asyncio.streams.StreamWriter = StreamWriter