\version "2.16.0"

\layout {
  \context {
    \Voice
    \consists #(let ((ccid 1))
                 (lambda (context)
                   (let ((id ccid))
                     (set! ccid (+ 1 ccid))
                     `((start-translation-timestep .
                         ,(lambda (trans)
                            (format #t "~A: ~A ~A\n" id (ly:context-property context 'currentBarNumber)
                              (ly:context-property context 'measurePosition))))
                       ))))
  }
}

\score {
  \relative c'' {
    c d << { e f } \\ { c d } >>
  }
}