D写utf8串.

import std;
void main() {
  ubyte[65536] buf;
  char[] usable_buf = cast(char[]) buf[];
  usable_buf.formattedWrite!"Blah %d blah %s"(123, "Это UTF-8 строка.");
  auto used = buf.length - usable_buf.length;
  writefln("%(%02X %)", buf[0 .. used]);
}