pre-allocate strings.Builder for UnderscoreEscaping

Author: boekkooi-impossiblecloud

model/metric.go

@@ -426,6 +426,7 @@ func EscapeName(name string, scheme EscapingScheme) string {
 		if IsValidLegacyMetricName(name) {
 			return name
 		}
+		escaped.Grow(len(name))
 		for i, b := range name {
 			if isValidLegacyRune(b, i) {
 				escaped.WriteRune(b)