private bool IsHeartbeatSecurityHeaderExist(byte[] userData)
{
// Peek "basic security header" at the front part of user data
int startIndex = 0;
TS_SECURITY_HEADER header = ParseTsSecurityHeader(
userData, ref startIndex, SecurityHeaderType.Basic);
// Check if this "security header" is for Server License Error PDU
return IsFlagExist((UInt16)header.flags, (UInt16)TS_SECURITY_HEADER_flags_Values.SEC_HEARTBEAT);
}