Merge pull request #32532 from dnephin/refactor-some-builder-parts

[builder] cleanup env dispatcher and Builder.build()
Upstream-commit: d2ab40e5b99bc2ab0abfea146544a20ce6081942
Component: engine

components/engine/api/types/backend/backend.go

@@ -100,8 +100,7 @@ type ContainerCommitConfig struct {
 	Changes []string
 }
 
-// ProgressWriter is an interface
-// to transport progress streams.
+// ProgressWriter is a data object to transport progress streams to the client
 type ProgressWriter struct {
 	Output             io.Writer
 	StdoutFormatter    *streamformatter.StdoutFormatter