my  $request = HTTP::Request::Common::POST( BOX,  
    [
    Content_Type => 'form-data',
    Authorization => "Bearer $token",
    Content => [ 
        attributes => $c,                #encoded json
        file       => [ "$Bin/test.txt" ],    #file_path
        ],
    ]
);


##</code><code>##

 sub build_json_request {
    my ($url) = @_;
    my $header = ['Authorization' => "Bearer $token", 'Content-Type' => 'form-data'];
    return HTTP::Request->new('POST', $url, $header, {attributes => $c, file=> [ "$Bin/upload.bak" ],} );
}

my $r = build_json_request (ENDPOINT );
my $res = $ua->request($r);