Remove old benchmark infra and replace with package-benchmark

**Motivation:**

Remove old benchmark infra which causes sendability warnings.

There's proper benchmark packages now and we should use them instead,
depend on: https://github.com/ordo-one/package-benchmark.git

**Modifications:**
Remove custom benchmark infra.
Adopt existing benchmark package -- this can also nicely track
allocations.

**Result:**

No sendability warnings; less deprecated benchmark infra

Author: ktoso

Benchmarks/.gitignore

@@ -0,0 +1 @@
+.build/

Benchmarks/.gitkeep

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+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Distributed Tracing open source project
+//
+// Copyright (c) 2020-2023 Apple Inc. and the Swift Distributed Tracing project
+// authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Benchmark
+import Tracing 
+
+let benchmarks = {
+    let defaultMetrics: [BenchmarkMetric] = [
+        .mallocCountTotal,
+    ]
+
+    Benchmark(
+        "NoopTracing.startSpan/endSpan",
+        configuration: .init(
+            metrics: defaultMetrics,
+            timeUnits: .nanoseconds,
+            scalingFactor: .mega
+        )
+    ) { benchmark in
+        let span = startSpan("name")
+        defer { span.end() }
+    }
+
+    Benchmark(
+        "NoopTracing.attribute: set, span.attributes['http.status_code'] = 200",
+        configuration: .init(
+            metrics: defaultMetrics,
+            timeUnits: .nanoseconds,
+            scalingFactor: .mega
+        )
+    ) { benchmark in
+        let span = startSpan("name")
+        span.attributes["http.status_code"] = 200
+        defer { span.end() }
+    }
+
+    Benchmark(
+        "NoopTracing.attribute: set, span.attributes.http.status_code = 200",
+        configuration: .init(
+            metrics: defaultMetrics,
+            timeUnits: .nanoseconds,
+            scalingFactor: .mega
+        )
+    ) { benchmark in
+        let span = startSpan("name")
+        span.attributes.http.statusCode = 200
+        defer { span.end() }
+    }
+}
+
+@dynamicMemberLookup
+struct HTTPAttributes: SpanAttributeNamespace {
+    var attributes: SpanAttributes
+
+    init(attributes: SpanAttributes) {
+        self.attributes = attributes
+    }
+
+    struct NestedSpanAttributes: NestedSpanAttributesProtocol {
+        init() {}
+
+        var method: Key<String> { "http.method" }
+        var statusCode: Key<Int> { "http.status_code" }
+    }
+}
+
+extension SpanAttributes {
+    var http: HTTPAttributes {
+        get {
+            .init(attributes: self)
+        }
+        set {
+            self = newValue.attributes
+        }
+    }
+}

Benchmarks/Benchmarks/TracingBenchmarks/AtrributeDSLBenchmark.swift

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+{
+  "pins" : [
+    {
+      "identity" : "hdrhistogram-swift",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/HdrHistogram/hdrhistogram-swift",
+      "state" : {
+        "revision" : "a69fa24d7b70421870cafa86340ece900489e17e",
+        "version" : "0.1.2"
+      }
+    },
+    {
+      "identity" : "package-benchmark",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/ordo-one/package-benchmark.git",
+      "state" : {
+        "revision" : "ddf6c1ae01e139120bcdb917ece52819ee69d47a",
+        "version" : "1.22.1"
+      }
+    },
+    {
+      "identity" : "package-jemalloc",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/ordo-one/package-jemalloc",
+      "state" : {
+        "revision" : "e8a5db026963f5bfeac842d9d3f2cc8cde323b49",
+        "version" : "1.0.0"
+      }
+    },
+    {
+      "identity" : "swift-argument-parser",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-argument-parser",
+      "state" : {
+        "revision" : "c8ed701b513cf5177118a175d85fbbbcd707ab41",
+        "version" : "1.3.0"
+      }
+    },
+    {
+      "identity" : "swift-atomics",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-atomics",
+      "state" : {
+        "revision" : "cd142fd2f64be2100422d658e7411e39489da985",
+        "version" : "1.2.0"
+      }
+    },
+    {
+      "identity" : "swift-numerics",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-numerics",
+      "state" : {
+        "revision" : "0a5bc04095a675662cf24757cc0640aa2204253b",
+        "version" : "1.0.2"
+      }
+    },
+    {
+      "identity" : "swift-service-context",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-service-context.git",
+      "state" : {
+        "revision" : "ce0141c8f123132dbd02fd45fea448018762df1b",
+        "version" : "1.0.0"
+      }
+    },
+    {
+      "identity" : "swift-system",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-system",
+      "state" : {
+        "revision" : "025bcb1165deab2e20d4eaba79967ce73013f496",
+        "version" : "1.2.1"
+      }
+    },
+    {
+      "identity" : "texttable",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/ordo-one/TextTable",
+      "state" : {
+        "revision" : "a27a07300cf4ae322e0079ca0a475c5583dd575f",
+        "version" : "0.0.2"
+      }
+    }
+  ],
+  "version" : 2
+}

Benchmarks/Package.resolved

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+// swift-tools-version: 5.9
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftCertificates open source project
+//
+// Copyright (c) 2023 Apple Inc. and the SwiftCertificates project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftCertificates project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import PackageDescription
+
+let package = Package(
+    name: "benchmarks",
+    platforms: [
+        .macOS("14"),
+    ],
+    dependencies: [
+        .package(path: "../"),
+        .package(url: "https://github.com/ordo-one/package-benchmark.git", from: "1.22.0"),
+    ],
+    targets: [
+        .executableTarget(
+            name: "TracingBenchmarks",
+            dependencies: [
+                .product(name: "Benchmark", package: "package-benchmark"),
+                .product(name: "Tracing", package: "swift-distributed-tracing"),
+            ],
+            path: "Benchmarks/TracingBenchmarks",
+            plugins: [
+                .plugin(name: "BenchmarkPlugin", package: "package-benchmark")
+            ]
+        ),
+    ]
+)