1GB per min on any half decent 4 core CPU

Hi.

I'm building an embedded Python No SQL database and I want to have a fast full-text search. Luckily I found tantivy-py.

Here are the problems I faced (not sure if they are bugs or just my misunderstanding):
I want to save ObjectId (similar to Mongo's ObjectId) in the doc.

>>> doc = tantivy.Document(b=b'abc')  
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-20-9693b204efef> in <module>
----> 1 doc = tantivy.Document(b=b'abc')

ValueError: Value unsupported b'abc'

If I use a separate method, it works:

>>> doc = tantivy.Document()          
>>> doc.add_bytes('b', b'abc')

However, when I want to get it back, I'm getting a list instead of bytes:

>>> doc.get_first('b')                
[97, 98, 99]

Also, when I retrieve this document (I follow the example at README), it contains no 'b' field:

>>> best_doc['b']
[]