Do not exit after pairing is finished

Android performs additional service
discovery during pairing, otherwise
pairing fails.

apps/pair.py

@@ -285,6 +285,7 @@ async def pair(
     mitm,
     bond,
     ctkd,
+    linger,
     io,
     prompt,
     request,
@@ -353,17 +354,20 @@ async def pair(
         if address_or_name is not None:
             print(color(f'=== Connecting to {address_or_name}...', 'green'))
             connection = await device.connect(address_or_name)
+            pairing_failure = False
 
             if not request:
                 try:
                     if mode == 'le':
                         await connection.pair()
                     else:
                         await connection.authenticate()
-                    return
                 except ProtocolError as error:
+                    pairing_failure = True
                     print(color(f'Pairing failed: {error}', 'red'))
-                    return
+
+            if not linger or pairing_failure:
+                return
         else:
             if mode == 'le':
                 # Advertise so that peers can find us and connect
@@ -413,6 +417,7 @@ def emit(self, record):
     help='Enable CTKD',
     show_default=True,
 )
+@click.option('--linger', default=True, is_flag=True, help='Linger after pairing')
 @click.option(
     '--io',
     type=click.Choice(
@@ -440,6 +445,7 @@ def main(
     mitm,
     bond,
     ctkd,
+    linger,
     io,
     prompt,
     request,
@@ -463,6 +469,7 @@ def main(
             mitm,
             bond,
             ctkd,
+            linger,
             io,
             prompt,
             request,