packagebitswapimport("time"blocks"github.com/jbenet/go-ipfs/blocks"u"github.com/jbenet/go-ipfs/util")typeExchangeinterface{// Block returns the block associated with a given key.// TODO(brian): pass a context instead of a timeout// TODO(brian): rename -> BlockGetBlock(ku.Key,timeouttime.Duration)(*blocks.Block,error)// HasBlock asserts the existence of this block// TODO(brian): rename -> HasBlock// TODO(brian): accept a value, not a pointer// TODO(brian): remove error return value. Should callers be concerned with// whether the block was made available on the network?HaveBlock(*blocks.Block)error}