/*!
\class BMidiConsumer MidiConsumer.h
\ingroup midi2
\ingroup libmidi2
\brief Receives MIDI events from a producer

A consumer is an object that knows how to deal with incoming MIDI events. A 
consumer can be connected to multiple producers at the same time. There is no 
way to find out which producers are connected to this consumer just by looking 
at the BMidiConsumer object; you will have to consult BMidiRoster for that.

A BMidiConsumer either represents a local consumer, i.e. a class extending from 
BMidiLocalConsumer, or is a proxy for a remote object published by another app. 

*/

/*!
\fn bigtime_t BMidiConsumer::Latency() const
\brief Returns the latency of this consumer

The latency is measured in microseconds. Producers should attempt to get MIDI 
events to this consumer by <I>(when - latency)</I>. You do this by subtracting 
the latency from the performance time when you spray the events (provided that 
you spray these events ahead of time, of course).

You cannot <I>set</I> the latency on a BMidiConsumer, only on a 
BMidiLocalConsumer.

The latency issue gets slightly more complicated when multiple endpoints are 
chained together, as in the following picture:

\verbatim
+-------+     +-------------+     +-------+
|       |     |             |     |       |
| prodA |---->| consB prodB |---->| consC |
|       |     |             |     |       |
+-------+     +-------------+     +-------+
  appA          appB (filter)       appC
\endverbatim

Suppose consC has 200ms latency, and consB has 100ms latency. If consB simply 
reports 100ms, then prodA will schedule its events for (t - 100), which is 
really 200ms too late. (Of course, producers send out their events as soon as 
possible, so depending on the load of the system, everything may work out just 
fine.)

ConsB should report the latency of the consumer that is hooked up to its 
output, consC, in addition to its own latency. In other words, the full 
downstream latency. So, the reported latency in this case would be 300ms. This 
also means that appB should change the latency of consB when prodB makes or 
breaks a connection, and when consC reports a latency change. (If multiple 
consumers are connected to prodB, you should take the slowest one.) 
Unfortunately, the Midi Kit provides no easy mechanism for doing any of this, 
so you are on your own here.

*/