Backfill runs into rate limits

[hbh7]

Hi,

I've been playing around with Matrix and this bridge recently, and I think I ran into a bug.

{"level":"error","user_id":"@hbh7:hbh7.com","component":"discordgo","caller":"restapi.go:298:RequestWithLockedBucket()","time":"2024-09-02T00:32:03.941281651Z","message":"rate limit unmarshal error, invalid character '<' looking for beginning of value"}
{"level":"error","channel_id":"<id>","channel_receiver":"<id>","room_id":"!<id>:hbh7.com","action":"initial backfill","room_id":"!<id>:hbh7.com","limit":1000000000,"error":"invalid character '<' looking for beginning of value","time":"2024-09-02T00:32:03.941323181Z","message":"Error collecting messages to forward backfill"}

Many of these messages are seen in the log shortly after starting an initial backfill, and it leaves many of the chats with entirely missing or partially incomplete histories.

I think it's related to this upstream issue: bwmarrin/discordgo#659

Seems like some sort of retry system should be implemented to work around rate limits, and/or some sort of built-in/configurable rate limiting within the bridge like I've seen in other bridges. The current path seems to be to ignore the failure and pretend everything imported successfully, which is definitely not ideal.

Hoping someone knowledgeable can build a solution. Thanks!