// Add this function to the bottom of swarm/storage/filestore.go

func (f *FileStore) Append(addr Address, data io.Reader, toEncrypt bool) (newAddr Address, wait func(), err error) {
	putter := NewHasherStore(f.ChunkStore, f.hashFunc, toEncrypt)
	return PyramidAppend(addr, data, putter, putter)
}