function readFixed32_end(buf, end) { // note that this uses `end`, not `pos`
    return (buf[end - 4]
          | buf[end - 3] << 8
          | buf[end - 2] << 16
          | buf[end - 1] << 24) >>> 0;
}
Reads a varint as a boolean.
@returns {boolean} Value read