code: @SuppressWarnings("unchecked")
      void setHeaderCaseInsensitive(final String name, final String value) {
          final MultiMap result = new MultiValueMap();
          
          for (final Object o: this.headers.keySet()) {
              final String key = (String) o; //fucking non-generics MultiMap
              if (!name.equalsIgnoreCase(key)) {
                    //copy all other headers to the result multimap
                  for(final String s: (Collection<String>)this.headers.get(o)) {
                      result.put(o, s);
                  }
              }
          }
          
          this.headers.clear();
          this.headers.putAll(result);
          this.addHeader(name, value);
      }
docs: Removes all occurrences of the given header in this stub response (using a case insensitive search)
  and sets its single value.
  @param name header name
  @param value header value