2.11.0.rc0

This feature release of the Ruby driver for MongoDB adds two major features:

1. A background thread in server connection pools to eagerly establish connections up to the minimum pool size
2. SRV polling for sharded deployments

This release of the Ruby driver bumps the minimum required Ruby version to 2.3, as well as minimum supported JRuby version to 9.2.

The following notable improvements have been made:

• RUBY-1563 Poll SRV records for mongos discovery
• RUBY-1605 Establish working connections in a background thread
• RUBY-1874 Add "connectionError" as a valid "reason" for a ConnectionCheckOutFailedEvent when connection set up fails
• RUBY-1884 Always wait for background threads to finish when closing resources
• RUBY-1885 Remove wait argument on client/cluster/etc. close/disconnect methods
• RUBY-1905 Indicate which server operations were attempted on and attempt number in driver-surfaced exceptions
• RUBY-1351 Allow unencoded subdelimiters in usernames and passwords
• RUBY-1622 Require Ruby 2.3+ in driver
• RUBY-1899 Drop JRuby 9.1 support
• RUBY-1745 Invalid auth mechanism is not reported until an operation is attempted on the client

The following notable bugs have been fixed:

• RUBY-1935 database#command attempts to retry as retryable read
• RUBY-1911 Average round trip time may become nil during server selection