Fix prompt mismatch issue for ios (#47004)

* Fix prompt mismatch issue for ios

Fixes #40884 #44463

*  If the command prompt is matched check if data is
   still pending to be read from buffer.
*  This fix adds a new timer `buffer_read_timeout`
   which will be trigerred after command prompt
   is matched and data is attempted to be read from channel.
   If not data is present of channel the timer will expire
   and response we be returned to calling function.

* Fix unit test failure

* Update to make buffer timeout float

* Update doc and fix review comment

* Fix CI issues

* Update doc

* Fix review comments

* Fix review comments

test/units/plugins/connection/test_network_cli.py

@@ -21,6 +21,7 @@ from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
 import re
+import time
 import json
 
 from io import StringIO
@@ -28,6 +29,7 @@ from io import StringIO
 from units.compat import unittest
 from units.compat.mock import patch, MagicMock
 
+from ansible.module_utils._text import to_text
 from ansible.errors import AnsibleConnectionFailure
 from ansible.playbook.play_context import PlayContext
 from ansible.plugins.loader import connection_loader
@@ -131,15 +133,14 @@ class TestConnectionClass(unittest.TestCase):
         device#
         """
 
-        mock__shell.recv.return_value = response
-
+        mock__shell.recv.side_effect = [response, None]
         output = conn.send(b'command', None, None, None)
 
         mock__shell.sendall.assert_called_with(b'command\r')
-        self.assertEqual(output, 'command response')
+        self.assertEqual(to_text(conn._command_response), 'command response')
 
         mock__shell.reset_mock()
-        mock__shell.recv.return_value = b"ERROR: error message device#"
+        mock__shell.recv.side_effect = [b"ERROR: error message device#"]
 
         with self.assertRaises(AnsibleConnectionFailure) as exc:
             conn.send(b'command', None, None, None)