private void checkLenient() throws IOException {
    if (!lenient) {
      throw syntaxError("Use JsonReader.setLenient(true) to accept malformed JSON");
    }
  }
Returns the next character in the stream that is neither whitespace nor a
part of a comment. When this returns, the returned character is always at
{@code buffer.getByte(0)}.
lottie/src/main/java/com/airbnb/lottie/parser/moshi/JsonUtf8Reader.java