#[repr(C)]
pub struct BlockContentsA {
    field_a: u32, // 0ffset 0
    field_b: i32, // 0ffset 4
    field_c: i32, // 0ffset 8
    field_d: f32, // 0ffset 12
    field_e: f32, // 0ffset 16
    // 4 bytes of padding at Offset 20
    field_f: f64, // Offset 24. Would be at offset 20 naturally, 
                  // but is bumped up to 24 because it has to be 
                  // at an offset multiple of 8
    ...
}