code: func Context(err error) []interface{} {
  	type contextor interface {
  		Context() []interface{}
  	}
  
  	var kvs []interface{}
  
  	ForEachCause(err, func(err error) bool {
  		if cerr, ok := err.(contextor); ok {
  			kvs = append(cerr.Context(), kvs...)
  		}
  
  		return true
  	})
  
  	return kvs
  }
docs: // Context extracts the context key-value pairs from an error (or error chain).