Support AVR (can not have heavy "fmt" package)

log.go

@@ -1,3 +1,5 @@
+//go:build !avr
+
 package csp
 
 import (
@@ -9,14 +11,16 @@ import (
 var Logger io.Writer = nil
 
 func log(format string, args ...interface{}) {
-	if Logger != nil {
-		Logger.Write([]byte(fmt.Sprintf(format, args...)))
+	if Logger == nil {
+		return
 	}
+	Logger.Write([]byte(fmt.Sprintf(format, args...)))
 }
 
 func logTs(format string, args ...interface{}) {
-	if Logger != nil {
-		args = append([]interface{}{time.Now().Format("15:04:05.000")}, args...)
-		Logger.Write([]byte(fmt.Sprintf("%s "+format, args...)))
+	if Logger == nil {
+		return
 	}
+	args = append([]interface{}{time.Now().Format("15:04:05.000")}, args...)
+	Logger.Write([]byte(fmt.Sprintf("%s "+format, args...)))
 }

log_avr.go

@@ -0,0 +1,24 @@
+//go:build avr
+
+package csp
+
+import (
+	"io"
+)
+
+var Logger io.Writer = nil
+
+func log(_ string, args ...interface{}) {
+	if Logger == nil {
+		return
+	}
+	for _, arg := range args {
+		if _, err := Logger.Write([]byte(arg.(string))); err != nil {
+			return
+		}
+	}
+}
+
+func logTs(format string, args ...interface{}) {
+	log(format, args...)
+}