Add pipelining benchmark (#171)

Author: adam-fowler

Benchmarks/ValkeyBenchmarks/ValkeyConnectionBenchmark.swift

@@ -22,6 +22,7 @@ import Valkey
 @available(valkeySwift 1.0, *)
 func connectionBenchmarks() {
     makeConnectionGETBenchmark()
+    makeConnectionPipelineBenchmark()
 }
 
 @available(valkeySwift 1.0, *)
@@ -51,3 +52,36 @@ func makeConnectionGETBenchmark() -> Benchmark? {
         try await serverMutex.withLock { $0 }?.close().get()
     }
 }
+
+@available(valkeySwift 1.0, *)
+@discardableResult
+func makeConnectionPipelineBenchmark() -> Benchmark? {
+    let serverMutex = Mutex<(any Channel)?>(nil)
+
+    return Benchmark("Connection: Pipeline benchmark", configuration: .init(metrics: defaultMetrics, scalingFactor: .kilo)) { benchmark in
+        let port = serverMutex.withLock { $0 }!.localAddress!.port!
+        let logger = Logger(label: "test")
+        try await ValkeyConnection.withConnection(
+            address: .hostname("127.0.0.1", port: port),
+            configuration: .init(),
+            logger: logger
+        ) { connection in
+            benchmark.startMeasurement()
+            for _ in benchmark.scaledIterations {
+                let foo = await connection.execute(
+                    GET("foo"),
+                    GET("foo"),
+                    GET("foo")
+                )
+                let result = try foo.2.get().map { String(buffer: $0) }
+                precondition(result == "Bar")
+            }
+            benchmark.stopMeasurement()
+        }
+    } setup: {
+        let server = try await makeLocalServer()
+        serverMutex.withLock { $0 = server }
+    } teardown: {
+        try await serverMutex.withLock { $0 }?.close().get()
+    }
+}