nl_tokens: Wraps a function to be called in a backoff loop .
pl_tokens: function FunctionCall ( fn , args , callback ) { events . EventEmitter . call ( this ) ; precond . checkIsFunction ( fn , 'Expected fn to be a function.' ) ; precond . checkIsArray ( args , 'Expected args to be an array.' ) ; precond . checkIsFunction ( <mask> , 'Expected callback to be a function.' ) ; this . function_ = fn ; this . arguments_ = args ; this . callback_ = callback ; this . lastResult_ = [ ] ; this . numRetries_ = 0 ; this . backoff_ = null ; this . strategy_ = null ; this . failAfter_ = - 1 ; this . retryPredicate_ = FunctionCall . DEFAULT_RETRY_PREDICATE_ ; this . state_ = FunctionCall . State_ . PENDING ; }