the [...] that you removed is

> At any given time a message may be in the ZeroMQ sender queue, the sender's kernel buffer, on the wire, in the receiver's kernel buffer or in the receiver's ZeroMQ receiver queue. Furthermore, a ZeroMQ socket can bind and/or connect to many peers. Each peer may have different performance characteristics and therefore a different queue depth. Any "queue depth" number is almost certainly wrong

The library doesn't hide stuff from you, it just refuses to show you information that might as well be a random number.

If you want to know how many peers are connected you use heartbeats instead of just blindly trusting that 1 tcp socket = 1 available peer.