in src/main/scala/com/gu/invoicing/invoice/Impl.scala [121:127]
def time[R](block: => R): R = {
val t0 = System.nanoTime()
val result = block // call-by-name
val t1 = System.nanoTime()
println("Elapsed time: " + (t1 - t0) / 1_000_000_000d + "s")
result
}