ymodem.py initial packet composition error

[ApiumJacob]

If I send a simple file called "hello.txt" using a program that I know has a working y-modem send protocol to another program that I know has a working y-modem receive program data transfer looks like (blue = sender, green = receiver, ymodem-ul is the command to start the receiver):

The initial packet payload consists of the filename + 0x00 + filesize + 0x00 padding.

The ymodem.py program is not adding the file size to the initial packet which is causing my receiver to reject the packet:

I'm not sure if either programs that I know work are compliant to the standard and the files size may be optional.

The checksum of the initial packet from ymodem.py does seem to be being calculated correctly.

[ApiumJacob]

I see that this issue is addressed in pull request #2