两个去中心化文件存储方案（服务）如何选择？
https://github.com/ethersphere/go-ethereum/wiki/IPFS-&-SWARM
https://www.reddit.com/r/ethereum/comments/3hbqbv/ipfs_vs_swarm/
https://www.reddit.com/r/ethereum/comments/4bms6v/what_is_the_difference_between_swarm_and_ipfs/
Swarm没用过，IPFS试过还比较简单。
