How to chunk a binary file

I have a variable with the binary file read it from a file:

${fileData}= Get Binary File ${CHUNK_GEOJSON_FILE_UPLOAD_PATH}

This keyword read the entire file, no arguments to determine the among of bytes to be read.

So, what I actually need is to save in ${fileData} only 1MB, or I need to separate the entire file into different chunks(1Mb) because I will use those chunks to upload the file by chunks using the PATCH (Request-library) from the tus protocol.

Any help will be appreciated

For this specific case, the best is to write a small Python function that you can use as a keyword.