feat: Add async sample for incrementing a value

samples/snippets/writes/write_increment_async.py

@@ -0,0 +1,30 @@
+# [START bigtable_write_increment_async]
+from google.cloud.bigtable.data import BigtableDataClientAsync
+from google.cloud.bigtable.data.mutations import AddToCell, RowMutationEntry
+from google.cloud.bigtable.data.exceptions import MutationsExceptionGroup
+
+async def write_increment_async(project_id, instance_id, table_id):
+    """Increments a value in a Bigtable table using the async client."""
+    async with BigtableDataClientAsync(project=project_id) as client:
+        table = client.get_table(instance_id, table_id)
+        row_key = "unique_device_ids_1"
+        try:
+            async with table.mutations_batcher() as batcher:
+                # The AddToCell mutation increments the value of a cell.
+                # The value must be a positive or negative integer.
+                reading = AddToCell(
+                    family="counters",
+                    qualifier="odometer",
+                    value=32304
+                )
+                await batcher.append(RowMutationEntry(row_key.encode("utf-8"), [reading]))
+        except MutationsExceptionGroup as e:
+            # MutationsExceptionGroup contains a FailedMutationEntryError for
+            # each mutation that failed.
+            for sub_exception in e.exceptions:
+                failed_entry: RowMutationEntry = sub_exception.entry
+                cause: Exception = sub_exception.__cause__
+                print(
+                    f"Failed mutation for row {failed_entry.row_key!r} with error: {cause!r}"
+                )
+# [END bigtable_write_increment_async]