test: add patch benchmark

tests/benchmarks/patch.bench.luau

@@ -0,0 +1,48 @@
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+
+local patch = require(ReplicatedStorage.DevPackages.CharmSync.patch)
+
+local USERS = 1000
+
+local function generate()
+	local users = {}
+
+	for user = 1, USERS do
+		users[user] = {
+			coins = math.random(1, 2),
+			gems = math.random(1, 2),
+		}
+	end
+
+	return { users = users }
+end
+
+local function update(state)
+	state = table.clone(state)
+	state.users = table.clone(state.users)
+
+	for user = 1, USERS do
+		if math.random() > 0.5 then
+			continue
+		end
+
+		state.users[user] = {
+			coins = math.random(1, 2),
+			gems = math.random(1, 2),
+		}
+	end
+
+	return state
+end
+
+return {
+	ParameterGenerator = function()
+		local state = generate()
+		return state, update(state)
+	end,
+	Functions = {
+		diff = function(_, a, b)
+			patch.diff(a, b)
+		end,
+	},
+}