long diskUsage = startDir.sizeInBytes();
long startDiskUsage = 0;
String[] files = startDir.list();
for(int i=0;i<files.length;i++) {
startDiskUsage += startDir.fileLength(files[i]);
}
for(int method=0;method<3;method++) {
// Start with 100 bytes more than we are currently using: