type File struct {
	Closef                       func() error
	Pathf                        func() string
	IDf                          func() int
	Levelf                       func() int
	Measurementf                 func(name []byte) tsi1.MeasurementElem
	MeasurementIteratorf         func() tsi1.MeasurementIterator
	HasSeriesf                   func(name []byte, tags models.Tags, buf []byte) (exists, tombstoned bool)
	TagKeyf                      func(name, key []byte) tsi1.TagKeyElem
	TagKeyIteratorf              func(name []byte) tsi1.TagKeyIterator
	TagValuef                    func(name, key, value []byte) tsi1.TagValueElem
	TagValueIteratorf            func(name, key []byte) tsi1.TagValueIterator
	SeriesIDIteratorf            func() tsdb.SeriesIDIterator
	MeasurementSeriesIDIteratorf func(name []byte) tsdb.SeriesIDIterator
	TagKeySeriesIDIteratorf      func(name, key []byte) tsdb.SeriesIDIterator
	TagValueSeriesIDIteratorf    func(name, key, value []byte) tsdb.SeriesIDIterator
	MergeSeriesSketchesf         func(s, t estimator.Sketch) error
	MergeMeasurementsSketchesf   func(s, t estimator.Sketch) error
	Retainf                      func()
	Releasef                     func()
	Filterf                      func() *bloom.Filter
}