public boolean startsWith(String prefix, int toffset) {
        // Note: toffset might be near -1>>>1.
        if (toffset < 0 || toffset > length() - prefix.length()) {
            return false;
        }
        byte ta[] = value;
        byte pa[] = prefix.value;
        int po = 0;
        int pc = pa.length;
        if (coder() == prefix.coder()) {
            int to = isLatin1() ? toffset : toffset << 1;
            while (po < pc) {
                if (ta[to++] != pa[po++]) {
                    return false;
                }
            }
老师这段中后部看不太懂