question: public Throwable appendLast ( Throwable ex ) { Throwable r = ex ; Set < Throwable > memory = new HashSet < Throwable > ( ) ; while ( ex . getCause ( ) != null ) { if ( memory . add ( ex ) ) { ex = ex . getCause ( ) ; } else { return r ; } } try { ex . initCause ( this ) ; } catch ( Throwable exc ) { } return r ; }
target:  Try appending this RxJavaAssemblyException as the very last cause of the given throwable.