Merge pull request !1369 from ms_yan/del_storage

Merge pull request !1365 from h.farahat/text_namespace

Merge pull request !1308 from h.farahat/string_tensor2

add support for MindRecord and TFRecord
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optimize tensorshape

optimize tensorshape and FlatIndex

TFRecord and MindRecord support for string tensor

Modify mem layout
Add new constructor
Add method Allocate

Change some GetMutableBuffer usages to AllocateBuffer

Merge pull request !1281 from Peilin/splitOp

implementation 99% complete

everything and tested except for repeatable shuffling

tested most basic/typical split usecases

cleanup

some more cleanup

fix CI

more ci fix

more ci fixes

more ci fix

more ci fix

more ci fix

added more tests, fixed some bugs

some more clean up and test cases

added shard/shuffle before split warning/error

addressed code review comments and ci

fixed ci

Merge pull request !1306 from EricZ/master

Merge pull request !1157 from ms_yan/concat_dataset

Merge pull request !1126 from xiefangqi/voc_support_detection

change to use __add__ operation instead ds.concat

Merge pull request !1123 from pengyanjun/generator_dataset_np_copy_problem

Merge pull request !979 from ms_yan/rename_columns

support for 1 specific dimension to be None, added validator

fix various CI complains

another round of CI fixes

ci

refactor parts of the code

code refactor

ci fix

comments added, fix bugs

address review comments

address review comments

review cmts

added simple perf test script

update pad code

perf imprv

Merge pull request !969 from liyong126/fix_mindrecord_pk_sampler

Merge pull request !872 from JunhanHu/generator_schema

Merge pull request !869 from JesseKLee/random_data_op

Merge pull request !603 from liyong126/update_pk_sampler

Merge pull request !671 from EricZ/master

Merge pull request !466 from h.farahat/deepcopy

Merge pull request !739 from yanghaitao/yht_map_python_multiprocessing_check

Added new testcase for multi iterator

Addressing review

Fixed typo