Description of problem:
When receiving a large amounts of messages over SSL using a receiver prefetch, the clients fails with an exception "An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full". This exception seems to originate from the SslAsynchIO class, method sslDataIn.


Version-Release number of selected component (if applicable):
any (e.g. MRG 2.3 but also in qpid 0.22)


How reproducible:
100%


Steps to Reproduce:
1) Create a large queue on a broker (C++ / Linux)
2) Start feeding messages into the queue using C++/Linux program (in my case I used approximately 1kB messages)
3) Connect with a receiver (C++/Windows) using SSL and prefetch 1000 (no client authentication, I used username & password)
4) Wait few seconds to see the error in the receiver

Particular reproducer program: see https://issues.apache.org/jira/secure/attachment/12595257/client.cpp.


Actual results:
Receiver stucks and logs:

debug Exception constructed: An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full.  (C:\some\path\source\qpid\cpp\src\qpid\sys\windows\SslAsynchIO.cpp:350)


Expected results:
No stuck consumer, no error.


Additional info:
1) Decreasing the capacity seems to improve the frequency with which the problem appears. However with 1MB messages, even capacity 1 doesn't seem to work.
2) Attempting to reproduce in-house, we aimed in the client stuck but without the error seen (could be logging issue, though).
3) Increasing the BufferCount value in AsynchIO.h from 4 to 5 seems to solve the problem - at least in the terms that the error doesn't reproduce anymore.