Prefetch data in timm_efficientdet (#1111)
Summary:
Upgrade the version of timm_efficientdet and fix the code.
Prefetch the data so that dataloader is not part of the picture.
Fixes https://github.com/pytorch/benchmark/issues/1102
Pull Request resolved: https://github.com/pytorch/benchmark/pull/1111
Reviewed By: FindHao
Differential Revision: D38720091
Pulled By: xuzhao9
fbshipit-source-id: 7b34fc05f7a374ed7c0349a8d42547e25a04624e
