Running several rb.init on same process will hit too many open files error

[frascuchon]

Describe the bug
Calling several times to rb.init ends by hitting a "Too many open files" error.

To Reproduce
Just run this code:

import rubrix as rb

for i in range(1000):
  rb.init()

Expected behavior
rb.init could be called multiple times without leaking resources.

Screenshots
N/A

Environment (please complete the following information):

• OS [e.g. iOS]: macOS
• Browser [e.g. chrome, safari]: N/A
• Rubrix Version [e.g. 0.10.0]: 0.16.0
• ElasticSearch Version [e.g. 7.10.2]: N/A
• Docker Image (optional) [e.g. rubrix:v0.10.0]: N/A

Additional context
N/A