InputStream object cannot be used with pandas

In this example:

```python
import logging
import os
from azure.cosmosdb.table.tableservice import TableService
import azure.functions as func
import pandas

def main(myblob: func.InputStream):
logging.info(f"Python blob trigger function processed blob \n"
f"Name: {myblob.name}\n"
f"Blob Size: {myblob.length} bytes")
df = pandas.read_excel(myblob, index_col=0)

table_service = TableService(account_name=os.getenv('TABLE_STORAGE_ACCOUNT_NAME'),
account_key=os.getenv('TABLE_STORAGE_KEY'))

records = df.to_dict(orient="records") 
for record in records:
table_service.insert_entity('ais', record)
```

Configured with function.json as:

```json
{
"scriptFile": "__init__.py",
"bindings": [
{
"name": "myblob",
"type": "blobTrigger",
"direction": "in",
"path": "ais/{name}.xlsx",
"connection": "anthonyshawstorage_STORAGE"
}
]
}
```

The script fails because `InputStream` does not implement the seek function. It _does_ implement `seakable()` as returning false, which is correct, but pandas doesn't adhere to that API so you get this error:

```default
Exception while executing function: Functions.BlobTrigger Result: Failure
Exception: UnsupportedOperation: seek
Stack: File "/azure-functions-host/workers/python/3.9/LINUX/X64/azure_functions_worker/dispatcher.py", line 355, in _handle__invocation_request
call_result = await self._loop.run_in_executor(
File "/usr/local/lib/python3.9/concurrent/futures/thread.py", line 52, in run
result = self.fn(*self.args, **self.kwargs)
File "/azure-functions-host/workers/python/3.9/LINUX/X64/azure_functions_worker/dispatcher.py", line 542, in __run_sync_func
return func(**params)
File "/home/site/wwwroot/BlobTrigger/__init__.py", line 13, in main
df = pandas.read_excel(myblob, index_col=0)
File "/home/site/wwwroot/.python_packages/lib/site-packages/pandas/util/_decorators.py", line 299, in wrapper
return func(*args, **kwargs)
File "/home/site/wwwroot/.python_packages/lib/site-packages/pandas/io/excel/_base.py", line 336, in read_excel
io = ExcelFile(io, storage_options=storage_options, engine=engine)
File "/home/site/wwwroot/.python_packages/lib/site-packages/pandas/io/excel/_base.py", line 1057, in __init__
ext = inspect_excel_format(
File "/home/site/wwwroot/.python_packages/lib/site-packages/pandas/io/excel/_base.py", line 942, in inspect_excel_format
stream.seek(0)
```

Technically, this is a bug in pandas, because it should check `seekable()` first.

Is there a way to make the inputstream seekable if it comes from blob storage?