套件： golang-github-nebulouslabs-errors-dev (0.0~git20170430.98e1f05-1.1)

errors with context, composition, and easy error checking

The errors package is an extension of and drop in replacement for the standard library errors package. Multiple errors can be composed into a single error with the Compose function, or a single error can be extended by adding context using the Extend function. The result can be checked for the presence of a specific error using Contains. If any of the underlying composed or extended errors or extensions match, Contains will return true.

This package is especially beneficial during testing, where you may wish to check for presence of a specific error, but that specific error may be extending another error or may have been extended by another function somewhere else in the call stack.