// NewCursor creates a C cursor from a Bucket.
func NewCursor(b *bolt.Bucket) *Cursor {
info := b.Tx().DB().Info()
root := b.Root()
c := &Cursor{C: new(C.bolt_cursor)}
C.bolt_cursor_init(c.C, unsafe.Pointer(&info.Data[0]), C.size_t(info.PageSize), C.pgid(root))
return c
}