#21804: Add RFC 6856 (UTF8) support to poplib.

Patch by Milan Oberkirch.
diff --git a/Lib/poplib.py b/Lib/poplib.py
index 4915628..f672390 100644
--- a/Lib/poplib.py
+++ b/Lib/poplib.py
@@ -71,6 +71,7 @@
             UIDL [msg]              uidl(msg = None)
             CAPA                    capa()
             STLS                    stls()
+            UTF8                    utf8()
 
     Raises one exception: 'error_proto'.
 
@@ -348,6 +349,12 @@
         return self._longcmd('UIDL')
 
 
+    def utf8(self):
+        """Try to enter UTF-8 mode (see RFC 6856). Returns server response.
+        """
+        return self._shortcmd('UTF8')
+
+
     def capa(self):
         """Return server capabilities (RFC 2449) as a dictionary
         >>> c=poplib.POP3('localhost')