Function check_multipart 

pub fn check_multipart(
    field: &str,
    size: u64,
    content_type: &str,
    rules: &Rules,
    max_part: u64,
) -> Result<(u64, u16)>

Checks the declared file against rules and lays it out in parts, as multipart_uploads does before creating the upload.

Errors

Error::Invalid on field when the size or type breaks rules, or the file needs parts over max_part.