rpc_util: revise limit reader N to maxReceiveMessageSize

[lichunzhu]

Currently, limitReader's stop bytes in decompress is set to maxReceiveMessageSize+1.

However, it seems that received message's length won't exceed maxReceiveMessageSize (we have a check before). It maxReceiveMessageSize is set to maxInt server can't read any data from decompress function because maxReceiveMessageSize+1 will overflow MAX_INT64, as the problem in pingcap/tidb-binlog#1152 (comment).

So I guess we can change this limit to maxReceiveMessageSize.

[linux-foundation-easycla]

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• ✅ login: lichunzhu / name: Chunzhu Li (ee47fc3)

[easwars]

However, it seems that received message's length won't exceed maxReceiveMessageSize (we have a check before).

This is true only when the anonymous interface with DecompressedSize() method is implemented, and this is currently true only for gzip.

And could you please clarify your motivation behind this change? Unless this is breaking something in a very fundamental way, we are inclined to not change the way things are currently.

Also, if you have a strong reason to go ahead and make this change, we would also like to see some tests added. Thanks.

[github-actions]

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