private byte[] OpenFile(uint requestId, string filePath, uint flags)
{
SFTPPacket packet =
new SFTPPacket(SFTPPacketType.SSH_FXP_OPEN)
.WriteUInt32(requestId)
.WriteAsString(_encoding.GetBytes(filePath))
.WriteUInt32(flags)
.WriteUInt32(0); // attribute flag
return WaitHandle(packet, requestId);
}