code: @Nonnull
      public BugInstance addMethod(@SlashedClassName String className, String methodName, String methodSig, int accessFlags) {
          addMethod(MethodAnnotation.fromForeignMethod(className, methodName, methodSig, accessFlags));
          return this;
      }
docs: Add a method annotation. If this is the first method annotation added, it
  becomes the primary method annotation.
  
  @param className
  name of the class containing the method
  @param methodName
  name of the method
  @param methodSig
  type signature of the method
  @param accessFlags
  accessFlags for the method
  @return this object