if totalLength == 0 {
		return 0
	}
	if totalLength == -1 {
		return -1
	}
	numShards := totalLength / e.blockSize
	lastBlockSize := totalLength % e.blockSize
	lastShardSize := ceilFrac(lastBlockSize, int64(e.dataBlocks))
	return numShards*e.ShardSize() + lastShardSize
}

// ShardFileOffset - returns the effective offset where erasure reading begins.