fix (voice): Fix data preconditions.

Fixes issue where voice session would start without member data.
Fixes issue where voice session would start without channel data.
Fixes issue on init where sessions would start without keys.
Fixes issue on guild join where sessions would start without keys.
Fixes issue in schedule where data cache key was built incorrectly.

src/tracking/voice/data.py

@@ -37,6 +37,39 @@ class VoiceTrackerData(Registry):
         deleted = Bool()
         _timestamp = Timestamp()
 
+        @classmethod
+        async def fetch_multiple(cls, *keys, create=True):
+            """
+            Fetch and optionally create multiple row, applying cache where possible.
+
+            Provided keys should be in the form (channelid, guildid)
+            Results will be provided as a map channelid -> Row
+            """
+            cidmap = {cid: gid for cid, gid in keys}
+
+            results = {}
+            to_fetch = set()
+            for cid in cidmap:
+                row = cls._cache_.get((cid,), None)
+                if row is None or row.data is None:
+                    to_fetch.add(cid)
+                else:
+                    results[cid] = row
+
+            if to_fetch:
+                rows = await cls.fetch_where(channelid=list(cidmap.keys()))
+                for row in rows:
+                    results[row.channelid] = row
+                    to_fetch.remove(row.channelid)
+            if to_fetch and create:
+                rows = await cls.table.insert_many(
+                    ('channelid', 'guildid', 'deleted'),
+                    *((cid, cidmap[cid], False) for cid in to_fetch)
+                ).with_adapter(cls._make_rows)
+                for row in rows:
+                    results[row.channelid] = row
+            return results
+
     class VoiceSessionsOngoing(RowModel):
         """
         Model describing currently active voice sessions.