move examples and experimentals to submodules

fix #171: add breaker to context converter to prevent critical bug wi…

…th http package integration

Merge pull request #160 from kamilsk/issue-158

fix #158: preserve context values

support go 1.16

fix #155: extend Action

fix #153: rename DoAsync to Go

Merge branch 'v4' into v5

fix #152: hide retriable error

fix #149: check error check semantic

handle panic