tokens: In this case , both the goroutines you start get the value 1001 , the so second time through both values passed into enqueue are odd ( you can see that as two using 1001s in your output ) so nothing writes to the queue , so there is nothing for the range queue loop to consume .
ner_tags: O O O O O O O O O O O O B-Value O O O O O O O O O O B-Function O O O O O O O O O B-Output_Block I-Output_Block O O O O O O O O O B-Data_Structure O O O O O O O B-Code_Block I-Code_Block O O O O