Track object usage (#399)

* Track object usage wip

* doh

* better sys exit

* Wrap up implementation of diagnostics

* add tests

* last bit of test coverage

* create map to determine bpp for textures

* Refactor

* More refactoring

* tweak

* Remove old print_report

* Add docs

* Small refactor for codegen

* small tweaks

* Cleaner way to handle space between totals

docs/utils.rst

@@ -3,6 +3,45 @@ Utils
 
 The wgpu library provides a few utilities. Note that most functions below need to be explictly imported.
 
+Logger
+------
+
+Errors, warnings, and info messages (including messages generated by
+wgpu-native) are logged using Python's default logging mechanics. The
+wgpu logger instance is in ``wgpu.logger``, but can also be obtained
+via:
+
+.. code-block:: py
+
+    import logging
+    logger = logging.getLogger("wgpu")
+
+
+Diagnostics
+-----------
+
+To print a full diagnostic report:
+
+.. code-block:: py
+
+    wgpu.diagnostics.print_report()
+
+To inspect (for example) the total buffer usage:
+
+.. code-block:: py
+
+    >>> counts = wgpu.diagnostics.object_counts.get_dict()
+    >>> print(counts["Buffer"])
+    {'count': 3, 'resource_mem': 784}
+
+
+.. autoclass:: wgpu._diagnostics.DiagnosticsRoot
+    :members:
+
+
+.. autoclass:: wgpu._diagnostics.Diagnostics
+    :members:
+
 
 Get default device
 ------------------