private String header(int offset) {
    /*
     * Note: This uses the original bytecode, not the
     * possibly-transformed one.
     */
    int opcode = bytes.getUnsignedByte(offset);
    String name = ByteOps.opName(opcode);

    if (opcode == ByteOps.WIDE) {
      opcode = bytes.getUnsignedByte(offset + 1);
      name += " " + ByteOps.opName(opcode);
    }

    return Hex.u2(offset) + ": " + name;
  }
Helper to produce the first bit of output for each instruction.

@param offset the offset to the start of the instruction
android/android_framework/dex-maker/src/main/java/com/android/dx/cf/direct/CodeObserver.java