Unicode docs.

doc/index.rst

@@ -16,6 +16,7 @@ Topics
    :maxdepth: 2
 
    migrating
+   unicode
    multiplexed
    events
    acknowledgments

doc/unicode.rst

@@ -0,0 +1,22 @@
+Unicode
+=======
+
+TornadIO2 supports unicode for all transports. When you send something, it will be automatically
+converted to the unicode (assuming that it is not unicode already).
+
+Few rules:
+
+1. ``send`` has following logic in place:
+	- If message is object or dictionary, it will be json encoded into unicode string
+	- If message is unicode, it will be sent as is
+	- If message is non-unicode, not an object and not a dictionary, it will be converted to string
+	and converted to unicode using utf-8 encoding. If your string is in some other encoding (multi-byte, etc),
+	it is up for you to handle encoding and pass your data in unicode (or utf-8 encoded).
+
+2. ``emit`` has similar logic:
+	- It will convert event name into unicode string (if it is not). It is expected that event name
+	will only use latin characters
+	- All ``emit`` arguments will be json encoded into unicode string
+
+3. All incoming messages will be automatically converted to unicode strings. You can expect to receive unicode
+strings in your message handler and events.