title: PdfDocument in PdfView is crash with unrecognised selector instance in Objective C
body: <p>I am using Xcode 9.4 with Objective C.
  I want display pdf file using PDFView as per the below code</p>
  
  <pre><code>PDFView * pdfView = [[PDFView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
  NSString* path = [[NSBundle mainBundle] pathForResource:@"abc" ofType:@"pdf"];
  NSData* data = [NSData dataWithContentsOfFile:path];
  PDFDocument *pdfDocument = [[PDFDocument alloc] initWithData:data];
  [pdfView setDocument:pdfDocument];
  </code></pre>
  
  <p>But it fails with SetDocument unrecognised selector instance along with below error.</p>
  
  <p>Error:</p>
  
  <p>-[PDFView setDocument:]: unrecognized selector sent to instance 0x101367c40</p>
  
  <p>error: Execution was interrupted, reason: Attempted to dereference an invalid ObjC Object or send it an unrecognized selector.
  The process has been returned to the state before expression evaluation.</p>
  
  <p>I am not able to identify the exact problem, please help.</p>
  
  <p>Thank you.</p>