code: @PublicAPI("Used by fb-contrib-eclipse-quickfixes to determine type of fix to apply")
      public static Map<String, Integer> getUnreplaceableCharsetEncodings() {
          Map<String, Integer> encodings = new HashMap<>((int) (UNREPLACEABLE_ENCODING_METHODS.size() * 1.6));
          for (Map.Entry<FQMethod, Integer> entry : UNREPLACEABLE_ENCODING_METHODS.entrySet()) {
              encodings.put(entry.getKey().toString(), entry.getValue());
          }
          return encodings;
      }
docs: used by external tools, lists the method signature checked for, for unreplaceable encoding methods
  
  @return a map of these methods