use DispatchData(bytesNoCopy:deallocator:) with custom deallocator

Author: albertaleksieiev

Foundation/URLSession/BodySource.swift

@@ -72,21 +72,23 @@ extension _BodyStreamSource : _BodySource {
         }
 
         let buffer = UnsafeMutableRawBufferPointer.allocate(byteCount: length, alignment: MemoryLayout<UInt8>.alignment)
-        defer { buffer.deallocate() }
 
         guard let pointer = buffer.baseAddress?.assumingMemoryBound(to: UInt8.self) else {
+            buffer.deallocate()
             return .error
         }
 
         let readBytes = self.inputStream.read(pointer, maxLength: length)
         if readBytes > 0 {
-            let dispatchData = DispatchData(bytes: UnsafeRawBufferPointer(buffer))
+            let dispatchData = DispatchData(bytesNoCopy: UnsafeRawBufferPointer(buffer), deallocator: .custom(nil, { buffer.deallocate() }))
             return .data(dispatchData.subdata(in: 0 ..< readBytes))
         }
         else if readBytes == 0 {
+            buffer.deallocate()
             return .done
         }
         else {
+            buffer.deallocate()
             return .error
         }
     }