+ Tie(streambuf* b, streambuf* l) : buf(b), logBuf(l) {}
+
+ int sync() override { return logBuf->pubsync(), buf->pubsync(); }
+ int overflow(int c) override { return log(buf->sputc((char)c), "<< "); }
+ int underflow() override { return buf->sgetc(); }
+ int uflow() override { return log(buf->sbumpc(), ">> "); }
+
+ streambuf *buf, *logBuf;
+
+ int log(int c, const char* prefix) {
+
+ static int last = '\n'; // Single log file
+
+ if (last == '\n')
+ logBuf->sputn(prefix, 3);
+
+ return last = logBuf->sputc((char)c);
+ }
+};
+
+class Logger {