Another approach.

misc/windows-enospc/passthrough.py

@@ -0,0 +1,38 @@
+"""
+Writing to non-blocking pipe can result in ENOSPC when using Unix APIs on
+Windows.  So, this program passes through data from stdin to stdout, using
+Windows APIs instead of Unix-y APIs.
+"""
+
+import sys
+
+from twisted.internet.stdio import StandardIO
+from twisted.internet import reactor
+from twisted.internet.protocol import Protocol
+from twisted.internet.interfaces import IHalfCloseableProtocol
+from twisted.internet.error import ReactorNotRunning
+from zope.interface import implementer
+
+@implementer(IHalfCloseableProtocol)
+class Passthrough(Protocol):
+    def readConnectionLost(self):
+        self.transport.loseConnection()
+
+    def writeConnectionLost(self):
+        try:
+            reactor.stop()
+        except ReactorNotRunning:
+            pass
+
+    def dataReceived(self, data):
+        self.transport.write(data)
+
+    def connectionLost(self, reason):
+        try:
+            reactor.stop()
+        except ReactorNotRunning:
+            pass
+
+
+std = StandardIO(Passthrough())
+reactor.run()