private void WriteFramePacket(byte[] data, int startBit, int endBit)
{
var lengthBits = endBit - startBit;
var frame = BitHelper.CopyBlock(data, startBit, lengthBits);
if (lengthBits % 8 != 0)
{
frame[^ 1] |= (byte)(0xFF >> (lengthBits % 8 + 1)); // padding