Swift 5.1 support

Use stdlib Result instead of TAsyncResult

Fix: deprecations for `withUnsafeBytes`

Bump CI job Xcode version

Hash (into)

Co-authored-by: Sophie Lambrakis <SLambrakis@users.noreply.github.com>
Co-authored-by: Alexander Edge <alex@alexedge.co.uk>
diff --git a/lib/swift/Sources/TCompactProtocol.swift b/lib/swift/Sources/TCompactProtocol.swift
index 5b302d3..81a51f5 100644
--- a/lib/swift/Sources/TCompactProtocol.swift
+++ b/lib/swift/Sources/TCompactProtocol.swift
@@ -371,10 +371,7 @@
     try ProtocolTransportTry(error: TProtocolError(message: "Transport Read Failed")) {
       buff = try self.transport.readAll(size: 8)
     }
-    
-    let i64: UInt64 = buff.withUnsafeBytes { (ptr: UnsafePointer<UInt8>) -> UInt64 in
-      return UnsafePointer<UInt64>(OpaquePointer(ptr)).pointee
-    }
+    let i64: UInt64 = buff.withUnsafeBytes { $0.load(as: UInt64.self) }
     let bits = CFSwapInt64LittleToHost(i64)
     return Double(bitPattern: bits)
   }