Added seek to buffer to fix xlwt asv failure

[WillAyd]

• closes ASV: occasional asv failures on xlwt #19779
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

Sample ASV results from this as follows. Across 5 runs I got the upstream/master error every time and none on HEAD

(pandas_dev) williams-imac:asv_bench williamayd$ asv continuous -f 1.1 upstream/master HEAD -b io.excel.Excel.time_read_excel --show-stderr · Creating environments · Discovering benchmarks ·· Uninstalling from conda-py3.6-Cython-matplotlib-numexpr-numpy-openpyxl-pytables-pytest-scipy-sqlalchemy-xlrd-xlsxwriter-xlwt. ·· Installing into conda-py3.6-Cython-matplotlib-numexpr-numpy-openpyxl-pytables-pytest-scipy-sqlalchemy-xlrd-xlsxwriter-xlwt.. · Running 2 total benchmarks (2 commits * 1 environments * 1 benchmarks) [ 0.00%] · For pandas commit hash 15cd9d2d: [ 0.00%] ·· Building for conda-py3.6-Cython-matplotlib-numexpr-numpy-openpyxl-pytables-pytest-scipy-sqlalchemy-xlrd-xlsxwriter-xlwt... [ 0.00%] ·· Benchmarking conda-py3.6-Cython-matplotlib-numexpr-numpy-openpyxl-pytables-pytest-scipy-sqlalchemy-xlrd-xlsxwriter-xlwt [ 50.00%] ··· Running io.excel.Excel.time_read_excel ok [ 50.00%] ···· ============ ============= engine ------------ ------------- openpyxl 133±4ms xlsxwriter 118±0.7ms xlwt 54.2±0.05ms ============ ============= [ 50.00%] · For pandas commit hash f4c9d966: [ 50.00%] ·· Building for conda-py3.6-Cython-matplotlib-numexpr-numpy-openpyxl-pytables-pytest-scipy-sqlalchemy-xlrd-xlsxwriter-xlwt... [ 50.00%] ·· Benchmarking conda-py3.6-Cython-matplotlib-numexpr-numpy-openpyxl-pytables-pytest-scipy-sqlalchemy-xlrd-xlsxwriter-xlwt [100.00%] ··· Running io.excel.Excel.time_read_excel 1/3 failed [100.00%] ···· ============ =========== engine ------------ ----------- openpyxl 130±0.7ms xlsxwriter 117±0.4ms xlwt failed ============ =========== [100.00%] ····· For parameters: 'xlwt' Traceback (most recent call last): File "/Users/williamayd/miniconda3/envs/pandas_dev/lib/python3.6/site-packages/asv/benchmark.py", line 867, in <module> commands[mode](args) File "/Users/williamayd/miniconda3/envs/pandas_dev/lib/python3.6/site-packages/asv/benchmark.py", line 844, in main_run result = benchmark.do_run() File "/Users/williamayd/miniconda3/envs/pandas_dev/lib/python3.6/site-packages/asv/benchmark.py", line 398, in do_run return self.run(*self._current_params) File "/Users/williamayd/miniconda3/envs/pandas_dev/lib/python3.6/site-packages/asv/benchmark.py", line 473, in run samples, number = self.benchmark_timing(timer, repeat, warmup_time, number=number) File "/Users/williamayd/miniconda3/envs/pandas_dev/lib/python3.6/site-packages/asv/benchmark.py", line 500, in benchmark_timing timing = timer.timeit(number) File "/Users/williamayd/clones/pandas/asv_bench/env/83b3be1235aa7b08e8a17448e2f70790/lib/python3.6/timeit.py", line 178, in timeit timing = self.inner(it, self.timer) File "<timeit-src>", line 6, in inner File "/Users/williamayd/miniconda3/envs/pandas_dev/lib/python3.6/site-packages/asv/benchmark.py", line 464, in <lambda> func = lambda: self.func(*param) File "/Users/williamayd/clones/pandas/asv_bench/benchmarks/io/excel.py", line 29, in time_read_excel read_excel(self.bio_read) File "/Users/williamayd/clones/pandas/asv_bench/env/83b3be1235aa7b08e8a17448e2f70790/lib/python3.6/site-packages/pandas/util/_decorators.py", line 172, in wrapper return func(*args, **kwargs) File "/Users/williamayd/clones/pandas/asv_bench/env/83b3be1235aa7b08e8a17448e2f70790/lib/python3.6/site-packages/pandas/util/_decorators.py", line 172, in wrapper return func(*args, **kwargs) File "/Users/williamayd/clones/pandas/asv_bench/env/83b3be1235aa7b08e8a17448e2f70790/lib/python3.6/site-packages/pandas/io/excel.py", line 315, in read_excel io = ExcelFile(io, engine=engine) File "/Users/williamayd/clones/pandas/asv_bench/env/83b3be1235aa7b08e8a17448e2f70790/lib/python3.6/site-packages/pandas/io/excel.py", line 391, in __init__ self.book = xlrd.open_workbook(file_contents=data) File "/Users/williamayd/clones/pandas/asv_bench/env/83b3be1235aa7b08e8a17448e2f70790/lib/python3.6/site-packages/xlrd/__init__.py", line 116, in open_workbook with open(filename, "rb") as f: TypeError: expected str, bytes or os.PathLike object, not NoneType SOME BENCHMARKS HAVE CHANGED SIGNIFICANTLY. 

[jreback]

lgtm. ping on green.

[codecov]

Codecov Report

Merging #19926 into master will not change coverage.
The diff coverage is n/a.

@@ Coverage Diff @@ ## master #19926 +/- ## ======================================= Coverage 91.66% 91.66% ======================================= Files 150 150 Lines 48974 48974 ======================================= Hits 44894 44894 Misses 4080 4080

Flag	Coverage Δ
#multiple	90.04% <ø> (ø)	⬆️
#single	41.85% <ø> (ø)	⬆️

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[TomAugspurger]

Thanks @WillAyd .