Proposal: NPipe()

[wsc1]

I would like to propose the addition of a function

NPipe(vSrc, vSnk Form, n int, p func(snkd, src []float64) error) (src Source, snk Sink)

which would

act like pipe, except

• the Form of src would be vSrc
• the Form of snk would be vSnk, and hence could differ
• calls to src.Receive and snk.Send would return an error if the block size were not n
• the function p, if not nil, would be called on every []float64 sent through the pipe and
  if it resulted in an error, then that error would be returned to both the source and sink side.
  If p is nil, and vSrc.Channels() != vSnk.Channels(), then a non-nil error would be returned.
  If p is nil, and vSrc.Channels() == v.Snk.Channels(), then it would effectively pass through
  the data without error.

This would

• allow a developer to easily guarantee synchonized buffer sizes, and have corresponding efficiency benefits
• allow for easy dynamic resampling and channel mapping and what not without needing to multiplex i/o beyond 1 input and 1 output.

Thoughts appreciated.