hadoop-compat/src/main/java/com/twitter/elephantbird/util/HadoopCompat.java
public static Counter getCounter(TaskInputOutputContext context, Enum<?> key) {
    return (Counter) invoke(GET_COUNTER_ENUM_METHOD, context, key);
  }
public static Counter getCounter(TaskInputOutputContext context, Enum<?> key) {
    return (Counter) invoke(GET_COUNTER_ENUM_METHOD, context, key);
  }
Hadoop 1 & 2 compatible context.getCounter()
@return {@link TaskInputOutputContext#getCounter(Enum key)}