Pass # of times called to TCPConnectionNotify.received

[SeanTAllen]

On non-Windows platforms, TCPConnection will read data off of a socket
until:

• there's no more data to read
• a max size is hit
• TCPConnectionNotify.received returns false

The last option was introduced via [RFC
to give the programmer more control of when to yield the scheduler. This
was a noble goal but is weakly implemented. In order to exercise better
control, the programmer needs an additional bit of information: the
number of times during this scheduler run that received has been
called.

As we began to use RFC #19 at Sendence it became clear that is wasn't
doing what we wanted. What we hoped to be able to do was read up to X
number of messages off the socket, inject them into our application and
then give up the scheduler.

Our initial implementation was to keep a counter of messages received in
our TCPConnectionNotify instances and when it hit a number such as 25
or 50, return false to give up the scheduler. This, however, didn't
accomplish what we wanted. The following scenario was possible:

Scheduler run results in 24 calls to received. When the next scheduler
run would occur, we'd get 1 more received call and return false. What
we really wanted was to read no more than 25 messages per scheduler
run.

In order to accomplish this, we added an additional parameter to
TCPConnectionNotify.received: the number of times during this
scheduler run that received has been called (inclusive of the existing
call). This gives much more fine-grained control over when to
"prematurely" give up the scheduler and play nice with other sockets in
the system.

You might think, "why not lower the max read size"? And this certainly
is something you could do, but lowering the max read size, lowers how
large of a chunk we read from the socket during a given system call. In
the case of a high-throughput system, that will greatly increase the
number of system calls thereby lowering performance.

Resolves #1773

[SeanTAllen]

Forgot to update the examples. Pushed a fix for that.