Handle incomplete reads (#290)

Handle incomplete reads

Author: ryanbrandenburg

src/Microsoft.Sbom.Parsers.Spdx22SbomParser/Parser/ParserUtils.cs

@@ -228,6 +228,12 @@ public static void GetMoreBytesFromStream(Stream stream, ref byte[] buffer, ref
 
             leftover.CopyTo(buffer);
             bytesRead = stream.Read(buffer.AsSpan(leftover.Length));
+
+            // stream.Read doesn't always return the whole buffer length, so we need to fill the rest
+            if (bytesRead + leftover.Length != buffer.Length)
+            {
+                bytesRead = stream.Read(buffer.AsSpan(bytesRead + leftover.Length));
+            }
         }
         else
         {