addFile method Null safety
Add a field name
to the form data.
file
will be added directly to the body, skipping encoding.
Implementation
void addFile(String name, String filePath,
{String? contentType, String? filename}) {
filename ??= basename(filePath);
contentType ??= mime(filename);
addBytes(name, io.File(filePath).readAsBytesSync(),
filename: filename, contentType: contentType);
}