chore: add adr

docs/decisions/2024-07-08-multiserver

@@ -0,0 +1,19 @@
+---
+Date: 2024/07/09
+Authors: @Xopherus, @shezadkhan137
+Status: Accepted
+---
+
+# Multi-Server Fair Weighted Queues
+
+## Context
+
+ZeroFox needs to prioritize messages within SQS queues, especially when services receive data from multiple sources with varying latency requirements. Prioritization is key to meeting SLAs for high-priority messages while ensuring lower-priority messages are not starved. Additionally, we need to dynamically allocate throughput based on message priority to ensure fairness and efficiency.
+
+## Decisions
+
+1. Implement an experimental Weighted Fair Queue algorithm as a decorator for the go-msg library (receiver). 
+This decorator, called `WeightedFairReceiver`, will enable message prioritization based on assigned weights.
+
+2. Implement a `MultiServer` wrapper around `WeightedFairReceiver`. 
+This server will consume messages from multiple underlying servers into a single receiver, guaranteeing consumption in proportion to assigned weights.