Merge pull request #205 from cschleiden/with-value

Expose `WithValue`

Author: cschleiden

workflow/context.go

@@ -14,6 +14,23 @@ func WithCancel(parent Context) (ctx Context, cancel CancelFunc) {
 	return sync.WithCancel(parent)
 }
 
+// WithValue returns a copy of parent in which the value associated with key is
+// val.
+//
+// Use context Values only for request-scoped data that transits processes and
+// APIs, not for passing optional parameters to functions.
+//
+// The provided key must be comparable and should not be of type
+// string or any other built-in type to avoid collisions between
+// packages using context. Users of WithValue should define their own
+// types for keys. To avoid allocating when assigning to an
+// interface{}, context keys often have concrete type
+// struct{}. Alternatively, exported context key variables' static
+// type should be a pointer or interface.
+func WithValue(parent Context, key, val interface{}) Context {
+	return sync.WithValue(parent, key, val)
+}
+
 func NewDisconnectedContext(ctx Context) Context {
 	return sync.NewDisconnectedContext(ctx)
 }