time: Add (*Ticker) Start()

[gopherbot]

by opennota:

Some use cases for tickers require stopping the ticker and restarting it later.  This
behaviour can be emulated using time.After, but it requires creating new timers each
time you want to restart it.  I suggest to add the following methods:

  // NewUnstartedTicker returns a new ticker, but does not start it.
  func NewUnstartedTicker(d Duration) *Ticker

  // Start starts stopped or unstarted ticker.
  func (*Ticker) Start()

[ianlancetaylor]

Comment 1:

A simple API is preferable.  We should not complicate it for an unusual use case, if
that use case can be implemented in some other way.  In particular, consider using a
Timer, which supports a Reset method.

Status changed to WontFix.