I didn't find any documentation on TiBlob. The TCPSocket.write documentation says that the arguments passed can be a blob or a string.
How can I create a blob data object to send binary data on the TCP Socket?
You get a blob from some methods & properties - like .toImage() - which you can then use as data for the socket.
I don't think it's possible to create one explicitly but you can fake it using files with createFile, write, close, open & then read - which returns a blob of the contents.