[pyke369#10] Synthesize NSInputStream delegate property to avoid exce…

…ptions

when using PKMultipartInputStream as body stream for NSURLSessionUploadTask.

PKMultipartInputStream.m

@@ -138,6 +138,7 @@ @interface PKMultipartInputStream()
 @end
 
 @implementation PKMultipartInputStream
+@synthesize delegate;
 - (void)updateLength
 {
     self.length = self.footer.length + [[self.parts valueForKeyPath:@"@sum.length"] unsignedIntegerValue];