1 files changed, 2 insertions, 71 deletions
diff --git a/Lib/asyncio/selector_events.py b/Lib/asyncio/selector_events.py
index fb86f8245b1..869d66e0c8f 100644
--- a/Lib/asyncio/selector_events.py
+++ b/Lib/asyncio/selector_events.py
@@ -338,77 +338,8 @@ class BaseSelectorEventLoop(base_events.BaseEventLoop):
         sock.close()
 
 
-class _FlowControlMixin(transports.Transport):
-    """All the logic for (write) flow control in a mix-in base class.
-
-    The subclass must implement get_write_buffer_size().  It must call
-    _maybe_pause_protocol() whenever the write buffer size increases,
-    and _maybe_resume_protocol() whenever it decreases.  It may also
-    override set_write_buffer_limits() (e.g. to specify different
-    defaults).
-
-    The subclass constructor must call super().__init__(extra).  This
-    will call set_write_buffer_limits().
-
-    The user may call set_write_buffer_limits() and
-    get_write_buffer_size(), and their protocol's pause_writing() and
-    resume_writing() may be called.
-    """
-
-    def __init__(self, extra=None):
-        super().__init__(extra)
-        self._protocol_paused = False
-        self.set_write_buffer_limits()
-
-    def _maybe_pause_protocol(self):
-        size = self.get_write_buffer_size()
-        if size <= self._high_water:
-            return
-        if not self._protocol_paused:
-            self._protocol_paused = True
-            try:
-                self._protocol.pause_writing()
-            except Exception as exc:
-                self._loop.call_exception_handler({
-                    'message': 'protocol.pause_writing() failed',
-                    'exception': exc,
-                    'transport': self,
-                    'protocol': self._protocol,
-                })
-
-    def _maybe_resume_protocol(self):
-        if (self._protocol_paused and
-            self.get_write_buffer_size() <= self._low_water):
-            self._protocol_paused = False
-            try:
-                self._protocol.resume_writing()
-            except Exception as exc:
-                self._loop.call_exception_handler({
-                    'message': 'protocol.resume_writing() failed',
-                    'exception': exc,
-                    'transport': self,
-                    'protocol': self._protocol,
-                })
-
-    def set_write_buffer_limits(self, high=None, low=None):
-        if high is None:
-            if low is None:
-                high = 64*1024
-            else:
-                high = 4*low
-        if low is None:
-            low = high // 4
-        if not high >= low >= 0:
-            raise ValueError('high (%r) must be >= low (%r) must be >= 0' %
-                             (high, low))
-        self._high_water = high
-        self._low_water = low
-
-    def get_write_buffer_size(self):
-        raise NotImplementedError
-
-
-class _SelectorTransport(_FlowControlMixin, transports.Transport):
+class _SelectorTransport(transports._FlowControlMixin,
+                         transports.Transport):
 
     max_size = 256 * 1024  # Buffer size passed to recv().