private void updateCurrentFieldName() {
        if (getCurrentContext() instanceof MapContext) {
            currentFieldName.pop();
            final String suffix = getCurrentContext().isMapKey() ? MAP_KEY_SUFFIX : MAP_VALUE_SUFFIX;
            currentFieldName.push(currentFieldName.peek() + suffix);
        }
    }
Update the current field name, if necessary.

<p>After every read/write operation in {@link MapContext},
the field name should toggle between the map's key and value.</p>
thrift/thrift0.13/src/main/java/com/linecorp/armeria/common/thrift/text/TTextProtocol.java