[BEAM-5879 ] Make write_record() in tfrecordio.py py3 compatible (#6953)
[BEAM-5879 ] Make write_record() in tfrecordio.py py3 compatible (#6953)


lukecwik/incubator-beam,apache/beam,RyanSkraba/beam,charlesccychen/beam,chamikaramj/beam,charlesccychen/beam,RyanSkraba/beam,markflyhigh/incubator-beam,lukecwik/incubator-beam,chamikaramj/beam,apache/beam,chamikaramj/beam,lukecwik/incubator-beam,apache/beam,mxm/incubator-beam,apache/beam,mxm/incubator-beam,robertwb/incubator-beam,charlesccychen/beam,apache/beam,chamikaramj/beam,apache/beam,markflyhigh/incubator-beam,robertwb/incubator-beam,markflyhigh/incubator-beam,chamikaramj/beam,charlesccychen/beam,chamikaramj/beam,markflyhigh/incubator-beam,RyanSkraba/beam,charlesccychen/incubator-beam,chamikaramj/beam,robertwb/incubator-beam,chamikaramj/beam,charlesccychen/beam,RyanSkraba/beam,apache/beam,lukecwik/incubator-beam,chamikaramj/beam,RyanSkraba/beam,robertwb/incubator-beam,lukecwik/incubator-beam,markflyhigh/incubator-beam,apache/beam,lukecwik/incubator-beam,robertwb/incubator-beam,lukecwik/incubator-beam,lukecwik/incubator-beam,RyanSkraba/beam,RyanSkraba/beam,chamikaramj/beam,robertwb/incubator-beam,robertwb/incubator-beam,charlesccychen/beam,iemejia/incubator-beam,robertwb/incubator-beam,lukecwik/incubator-beam,markflyhigh/incubator-beam,iemejia/incubator-beam,lukecwik/incubator-beam,robertwb/incubator-beam,apache/beam,apache/beam,charlesccychen/incubator-beam,apache/beam,robertwb/incubator-beam,charlesccychen/incubator-beam,markflyhigh/incubator-beam,charlesccychen/beam