Rust learnings

byteorder, Cursor, buffer

• You get the write trait only on Cursors that contain &mut reference of whatever it is holding.
• If your Cursor contains &mut [u8] (slices are pointers to heaps vectors in rust), and the vector is 0 sized. All write will fail as there is no space on the heap to write to. And Cursor cannot extend a [u8] as they are simple slices
  • Instead, make a cursor of &mut Vec<u8> which will be grown as required by Cursor during write.
• Cursors can be converted to a nice vector after all writes using get_ref().to_vec()