THRIFT-5855: Add swift fuzzers

Add fuzzers for Swift support, to improve the reliability/robustness of the implementation
diff --git a/lib/swift/FuzzTesting/Package.swift b/lib/swift/FuzzTesting/Package.swift
new file mode 100644
index 0000000..81ce5b4
--- /dev/null
+++ b/lib/swift/FuzzTesting/Package.swift
@@ -0,0 +1,88 @@
+// swift-tools-version:5.5
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+import PackageDescription
+
+let package = Package(
+    name: "ThriftFuzzTesting",
+    dependencies: [
+        .package(name: "Thrift", path: "../")
+    ],
+    targets: [
+        // Generated code from Thrift definitions
+        .target(
+            name: "Fuzz",
+            dependencies: ["Thrift"],
+            path: "Sources/Fuzz"
+        ),
+        // Common utilities for fuzzing
+        .target(
+            name: "FuzzCommon",
+            dependencies: ["Thrift", "Fuzz"],
+            path: "Sources/FuzzCommon"
+        ),
+        .executableTarget(
+            name: "FuzzParseBinary",
+            dependencies: ["FuzzCommon", "Thrift", "Fuzz"],
+            path: "Sources/FuzzParseBinary",
+            linkerSettings: [
+                .unsafeFlags(["-sanitize=fuzzer"])
+            ]
+        ),
+        .executableTarget(
+            name: "FuzzRoundtripBinary",
+            dependencies: ["FuzzCommon", "Thrift", "Fuzz"],
+            path: "Sources/FuzzRoundtripBinary",
+            linkerSettings: [
+                .unsafeFlags(["-sanitize=fuzzer"])
+            ]
+        ),
+        .executableTarget(
+            name: "FuzzParseCompact",
+            dependencies: ["FuzzCommon", "Thrift", "Fuzz"],
+            path: "Sources/FuzzParseCompact",
+            linkerSettings: [
+                .unsafeFlags(["-sanitize=fuzzer"])
+            ]
+        ),
+        .executableTarget(
+            name: "FuzzRoundtripCompact",
+            dependencies: ["FuzzCommon", "Thrift", "Fuzz"],
+            path: "Sources/FuzzRoundtripCompact",
+            linkerSettings: [
+                .unsafeFlags(["-sanitize=fuzzer"])
+            ]
+        ),
+        .executableTarget(
+            name: "FuzzParseJSON",
+            dependencies: ["FuzzCommon", "Thrift", "Fuzz"],
+            path: "Sources/FuzzParseJSON",
+            linkerSettings: [
+                .unsafeFlags(["-sanitize=fuzzer"])
+            ]
+        ),
+        .executableTarget(
+            name: "FuzzRoundtripJSON",
+            dependencies: ["FuzzCommon", "Thrift", "Fuzz"],
+            path: "Sources/FuzzRoundtripJSON",
+            linkerSettings: [
+                .unsafeFlags(["-sanitize=fuzzer"])
+            ]
+        )
+    ]
+) 
\ No newline at end of file