Trainer + Dataloaders (#27)

Co-authored-by: Laughing-q <1185102784@qq.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>
Co-authored-by: Ayush Chaurasia <ayushchaurasia@Ayushs-MacBook-Pro.local>
Co-authored-by: Ayush Chaurasia <ayush.chuararsia@gmail.com>

ultralytics/yolo/utils/loggers/__init__.py

@@ -0,0 +1,3 @@
+from .base import default_callbacks
+
+__all__ = ["default_callbacks"]

ultralytics/yolo/utils/loggers/base.py

@@ -0,0 +1,32 @@
+def before_train(trainer):
+    # Initialize tensorboard logger
+    pass
+
+
+def on_epoch_start(trainer):
+    pass
+
+
+def on_batch_start(trainer):
+    pass
+
+
+def on_val_start(trainer):
+    pass
+
+
+def on_val_end(trainer):
+    pass
+
+
+def on_model_save(trainer):
+    pass
+
+
+default_callbacks = {
+    "before_train": before_train,
+    "on_epoch_start": on_epoch_start,
+    "on_batch_start": on_batch_start,
+    "on_val_start": on_val_start,
+    "on_val_end": on_val_end,
+    "on_model_save": on_model_save}