If you depend on Tokio 0.2, and a crate depends on =0.1.11, then cargo should include Tokio twice in the binary. Note that 0.2.2 is not the newest version of Tokio.
I'm sorry I wasn't precise enough: ldap3 doesn't explicitely depends on version 0.1.11, but a workaround for a bug it to force it to use 0.1.11 of the 0.1.x series.
Thanks for the highlight on 0.2.2 not being the latest