ruby client hangs when trying to use a sasl protected bucket

This simple ruby script:

require 'couchbase'
c = Couchbase.new('http://localhost:11211/pools/default/buckets/sasl', :password => 'sasl')

Hangs. Here's the stack trace:

#0 0x00007fff83746c0a in kevent ()
#1 0x00000001005a45f5 in kq_dispatch ()
#2 0x0000000100593cdc in event_base_loop ()
#3 0x000000010058257a in libcouchbase_wait ()
#4 0x00000001002f5824 in cb_bucket_init ()
#5 0x000000010016d034 in vm_call0 ()
#6 0x00000001001721ee in rb_funcall2 ()
#7 0x00000001002f4bc7 in cb_bucket_new ()
#8 0x00000001001779c3 in vm_call_method ()
#9 0x0000000100162d23 in vm_exec_core ()
#10 0x000000010016b873 in vm_exec ()
#11 0x000000010016c0c0 in eval_string_with_cref ()
#12 0x000000010016c7e2 in rb_f_eval ()
#13 0x00000001001779c3 in vm_call_method ()
#14 0x0000000100162d23 in vm_exec_core ()
#15 0x000000010016b873 in vm_exec ()
#16 0x0000000100179d51 in loop_i ()
#17 0x000000010003bdb7 in rb_rescue2 ()
#18 0x000000010015e9e6 in rb_f_loop ()
#19 0x00000001001779c3 in vm_call_method ()
#20 0x0000000100162d23 in vm_exec_core ()
#21 0x000000010016b873 in vm_exec ()
#22 0x00000001001799d4 in catch_i ()
#23 0x000000010015dbd5 in rb_catch_obj ()
#24 0x000000010015e8a0 in rb_f_catch ()
#25 0x00000001001779c3 in vm_call_method ()
#26 0x0000000100162d23 in vm_exec_core ()
#27 0x000000010016b873 in vm_exec ()
#28 0x00000001001799d4 in catch_i ()
#29 0x000000010015dbd5 in rb_catch_obj ()
#30 0x000000010015e8a0 in rb_f_catch ()
#31 0x00000001001779c3 in vm_call_method ()
#32 0x0000000100162d23 in vm_exec_core ()
#33 0x000000010016b873 in vm_exec ()
#34 0x000000010016bb7b in rb_iseq_eval_main ()
#35 0x000000010003c022 in ruby_exec_internal ()
#36 0x000000010003eb2c in ruby_run_node ()
#37 0x0000000100000aef in main ()