Added helpers to pass Loggers through context.Context.

lib/log/context.go

+package log
+
+import "context"
+
+type loggerContextKeyType int
+
+const loggerContextKey loggerContextKeyType = 0
+
+func WithLogger(ctx context.Context, logger RawLogger) context.Context {
+	return context.WithValue(ctx, loggerContextKey, logger)
+}
+
+func FromContext(ctx context.Context) *Logger {
+	if logger, ok := ctx.Value(loggerContextKey).(RawLogger); ok {
+		return &Logger{logger}
+	}
+	return DefaultLogger
+}