Fix for issues with callback userData MultipartReader always passes an uninitialized pointer as the userData argument for all callbacks, and a MultipartReader instance's userData cannot be set externally. Modified MultipartReader to initialize and expose the userData property as in MultipartParser.
Fix for issues with callback userData
MultipartReader always passes an uninitialized pointer as the userData argument for all callbacks, and a MultipartReader instance's userData cannot be set externally.
Modified MultipartReader to initialize and expose the userData property as in MultipartParser.

FooBarWidget/multipart-parser,FooBarWidget/multipart-parser,FooBarWidget/multipart-parser