What is the difference between open_timeout and read_timeout in sunspot

Question

I need a way to increase the sunspot query timeout in local development. As I was checking the sunspot code I got this code in sunspot.

solr:
    hostname: localhost
    port: 8983
    log_level: WARNING
    path: /solr/production
    read_timeout: 20
    open_timeout: 1
  auto_index_callback: after_commit
  auto_remove_callback: after_commit

Here we have two things read_timeout and open_timeout which looks similar to my problem. Since there is no documentation for it. So, can anybody tell me the purpose of both the things