go-context - jbenet's CONText EXTensions

https://godoc.org/github.com/jbenet/go-context

• WithDeadlineFraction: https://godoc.org/github.com/jbenet/go-context/ext#WithDeadlineFraction
• WithParents: https://godoc.org/github.com/jbenet/go-context/ext#WithParents
• io.{Reader, Writer}: https://godoc.org/github.com/jbenet/go-context/io