diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3ba0ee7..465718b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -65,16 +65,18 @@ variable.
 #### Other Changes
 
 - A client certificate can now have an empty ``commonName`` field.
-- For the ``JetforceApplication``, named capture groups in a route's regex
-  pattern will now be passed as keyword arguments to the wrapped function. See
+- ``JetforceApplication.route()`` - named capture groups in regex patterns will
+  now be passed as keyword arguments to the wrapped function. See
   examples/pagination.py for an example of how to use this feature.
-- A ``CompositeApplication`` class is now included to support virtual hosting
-  by composing multiple applications behind the same jetforce server. See
+- ``CompositeApplication`` - A class is now included to support composing
+  composing multiple applications behind the same jetforce server. See
   examples/vhost.py for an example of how to use this feature.
-- CGI variables - ``SCRIPT_NAME`` and ``PATH_INfO`` have been changed to match
+- CGI variables - ``SCRIPT_NAME`` and ``PATH_INFO`` have been changed to match
   their intended usage as defined in RFC 3875.
 - CGI variables - ``TLS_CIPHER`` and ``TLS_VERSION`` have been added and
   contain information about the established TLS connection.
+- Applications can now optionally return ``Deferred`` objects instead of bytes,
+  in order to support full-blown asynchronous coroutines.
 
 ### v0.2.3 (2020-05-24)
 
diff --git a/examples/guestbook.py b/examples/guestbook.py
index 76b3516..09bdc62 100644
--- a/examples/guestbook.py
+++ b/examples/guestbook.py
@@ -5,18 +5,13 @@ This is an example of how to return a 10 INPUT request to the client and
 retrieve their response by parsing the URL query string.
 
 This example stores the guestbook inside of a persistent sqlite database.
-Because each request will run inside of a separate thread, we must create a new
-connection object inside of the request handler instead of re-using a global
-database connection. This thread-safety can be disabled in sqlite3 by using the
-check_same_thread=False argument, but then it's up to you to ensure that only
-connection request is writing to the database at any given time.
 """
 import sqlite3
 from datetime import datetime
 
 from jetforce import GeminiServer, JetforceApplication, Response, Status
 
-DB = "/tmp/guestbook.sqlite"
+db = sqlite3.connect("/tmp/guestbook.sqlite", detect_types=sqlite3.PARSE_DECLTYPES)
 
 SCHEMA = """
 CREATE TABLE IF NOT EXISTS guestbook (
@@ -25,8 +20,7 @@ CREATE TABLE IF NOT EXISTS guestbook (
     message TEXT
 )
 """
-with sqlite3.connect(DB) as c:
-    c.execute(SCHEMA)
+db.execute(SCHEMA)
 
 
 app = JetforceApplication()
@@ -36,16 +30,14 @@ app = JetforceApplication()
 def index(request):
     lines = ["Guestbook", "=>/submit Sign the Guestbook"]
 
-    with sqlite3.connect(DB, detect_types=sqlite3.PARSE_DECLTYPES) as c:
-        for row in c.execute("SELECT * FROM guestbook ORDER BY created_at"):
-            ip_address, created_at, message = row
-            line = f"{created_at:%Y-%m-%d} - [{ip_address}] {message}"
-            lines.append("")
-            lines.append(line)
+    for row in db.execute("SELECT * FROM guestbook ORDER BY created_at"):
+        ip_address, created_at, message = row
+        line = f"{created_at:%Y-%m-%d} - [{ip_address}] {message}"
+        lines.append("")
+        lines.append(line)
 
     lines.extend(["", "...", ""])
     body = "\n".join(lines)
-
     return Response(Status.SUCCESS, "text/gemini", body)
 
 
@@ -55,9 +47,8 @@ def submit(request):
         message = request.query[:256]
         created = datetime.now()
         ip_address = request.environ["REMOTE_HOST"]
-        with sqlite3.connect(DB) as c:
-            values = (ip_address, created, message)
-            c.execute("INSERT INTO guestbook VALUES (?, ?, ?)", values)
+        values = (ip_address, created, message)
+        db.execute("INSERT INTO guestbook VALUES (?, ?, ?)", values)
         return Response(Status.REDIRECT_TEMPORARY, "")
     else:
         return Response(Status.INPUT, "Enter your message (max 256 characters)")
diff --git a/jetforce/protocol.py b/jetforce/protocol.py
index 2a67e08..a7bacad 100644
--- a/jetforce/protocol.py
+++ b/jetforce/protocol.py
@@ -106,13 +106,12 @@ class GeminiProtocol(LineOnlyReceiver):
             # Yield control of the event loop
             await deferLater(self.server.reactor, 0)
             while True:
-                try:
-                    data = await maybeDeferred(response_generator.__next__)
-                    self.write_body(data)
-                    # Yield control of the event loop
-                    await deferLater(self.server.reactor, 0)
-                except StopIteration:
+                data = await maybeDeferred(response_generator.__next__)
+                if data is None:
                     break
+                self.write_body(data)
+                # Yield control of the event loop
+                await deferLater(self.server.reactor, 0)
         except Exception:
             self.server.log_message(traceback.format_exc())
             self.write_status(Status.CGI_ERROR, "An unexpected error occurred")