public Builder addInterceptor(Interceptor interceptor) {
      if (interceptors == null) {
        interceptors = new ArrayList<>();
      }
      interceptors.add(interceptor);
      return this;
    }
Add an interceptor.

@param interceptor the interceptor to add
@return the builder
@since 1.3.0
xlog/src/main/java/com/elvishew/xlog/LogConfiguration.java