Print size of the message in very verbose mode (#181)

Adds -vv flag for "very verbose".
Includes estimated message size when enabled. The size is an estimate because it is the canonical size for the proto message, but not necessarily its actual on-the-wire size.

format_test.go

@@ -120,12 +120,14 @@ func TestHandler(t *testing.T) {
 
 	for _, format := range []Format{FormatJSON, FormatText} {
 		for _, numMessages := range []int{1, 3} {
-			for _, verbose := range []bool{true, false} {
+			for verbosityLevel := 0; verbosityLevel <= 2; verbosityLevel++ {
 				name := fmt.Sprintf("%s, %d message(s)", format, numMessages)
-				if verbose {
-					name += ", verbose"
+				if verbosityLevel > 0 {
+					name += fmt.Sprintf(", verbosityLevel=%d", verbosityLevel)
 				}
 
+				verbose := verbosityLevel > 0
+
 				_, formatter, err := RequestParserAndFormatter(format, source, nil, FormatOptions{IncludeTextSeparator: !verbose})
 				if err != nil {
 					t.Errorf("Failed to create parser and formatter: %v", err)
@@ -133,7 +135,11 @@ func TestHandler(t *testing.T) {
 				}
 
 				var buf bytes.Buffer
-				h := NewDefaultEventHandler(&buf, source, formatter, verbose)
+				h := &DefaultEventHandler{
+					Out:            &buf,
+					Formatter:      formatter,
+					VerbosityLevel: verbosityLevel,
+				}
 
 				h.OnResolveMethod(md)
 				h.OnSendHeaders(reqHeaders)
@@ -148,6 +154,9 @@ func TestHandler(t *testing.T) {
 					expectedOutput += verbosePrefix
 				}
 				for i := 0; i < numMessages; i++ {
+					if verbosityLevel > 1 {
+						expectedOutput += verboseResponseSize
+					}
 					if verbose {
 						expectedOutput += verboseResponseHeader
 					}
@@ -226,6 +235,9 @@ Response trailers received:
 a: 1
 b: 2
 c: 3
+`
+	verboseResponseSize = `
+Estimated response size: 100 bytes
 `
 	verboseResponseHeader = `
 Response contents: