add describe

progressbar.go

@@ -265,6 +265,12 @@ func (p *ProgressBar) Clear() error {
 	return clearProgressBar(p.config, p.state)
 }
 
+// Describe will change the description shown before the progress, which
+// can be changed on the fly (as for a slow running process).
+func (p *ProgressBar) Describe(description string) {
+	p.config.description = description
+}
+
 // render renders the progress bar, updating the maximum
 // rendered line width. this function is not thread-safe,
 // so it must be called with an acquired lock.

progressbar_test.go

@@ -216,3 +216,13 @@ func md5sum(filePath string) (result string, err error) {
 	result = hex.EncodeToString(hash.Sum(nil))
 	return
 }
+
+func ExampleDescribe() {
+	bar := NewOptions(100, OptionSetWidth(10), OptionSetRenderBlankState(false))
+	bar.Reset()
+	time.Sleep(1 * time.Second)
+	bar.Describe("performing axial adjustements")
+	bar.Add(10)
+	// Output:
+	// performing axial adjustements  10% |█         |  [1s:9s]
+}