Major Description
But works great if run on a LCB_TYPE_BUCKET. Here's the stack trace I see:
```* thread #2, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
- frame #0: 0x00007fff71ce7732 libsystem_platform.dylib`_platform_strlen + 18
frame #1: 0x00000001025b05ee libcouchbase.2.dylib`Json::Value::Value(char const*) [inlined] Json::Value::Value(this=0x00007ffeefbfe2a0, value=0x0000000000000000) at lcb-jsoncpp.cpp:2543:79
frame #2: 0x00000001025b05cf libcouchbase.2.dylib`Json::Value::Value(this=0x00007ffeefbfe2a0, value=0x0000000000000000) at lcb-jsoncpp.cpp:2541
frame #3: 0x0000000102591707 libcouchbase.2.dylib`lcb::Server::purge_single(this=0x000000010044f1a0, pkt=0x0000000100859000, err=LCB_ERR_TIMEOUT) at mcserver.cc:745:21
frame #4: 0x0000000102522686 libcouchbase.2.dylib`mcreq_pipeline_timeout(pl=0x000000010044f1a0, err=LCB_ERR_TIMEOUT, failcb=(libcouchbase.2.dylib`fail_callback(mc_pipeline_st*, mc_packet_st*, lcb_STATUS, void*) at mcserver.cc:616), cbarg=0x0000000000000000, now=86400017969407) at mcreq.c:915:13
frame #5: 0x000000010258f18d libcouchbase.2.dylib`lcb::Server::purge(this=0x000000010044f1a0, error=<unavailable>, now=<unavailable>, policy=REFRESH_ONFAILED) at mcserver.cc:782:20
frame #6: 0x000000010258f4de libcouchbase.2.dylib`lcb::Server::io_timeout(this=0x000000010044f1a0) at mcserver.cc:863:19
frame #7: 0x000000010252a063 libcouchbase.2.dylib`timer_callback(sock=<unavailable>, which=<unavailable>, arg=0x000000010041f550) at timer.c:43:5
frame #8: 0x000000010251204f libcouchbase.2.dylib`run_loop(io=0x000000010044c280, is_tick=0) at plugin-select.c:274:17
frame #9: 0x000000010259d6dd libcouchbase.2.dylib`::lcb_wait(instance=0x000000010044e1f0, flags=<unavailable>) at wait.cc:109:5
frame #10: 0x00000001024db172 _libcouchbase.cpython-37m-darwin.so`pycbc_common_vars_wait [inlined] pycbc_oputil_wait_common(self=<unavailable>, context=<unavailable>) at oputil.c:702:5 [opt]
frame #11: 0x00000001024db132 _libcouchbase.cpython-37m-darwin.so`pycbc_common_vars_wait(cv=0x00007ffeefbfe6b0, self=0x0000000105d5ee60, context=<unavailable>) at oputil.c:205 [opt]
frame #12: 0x00000001024d7edd libcouchbase.cpython-37m-darwin.so`pycbc_Bucket_ping_real(self=<unavailable>, args=<unavailable>, kwargs=<unavailable>, context=0x000000010041f6d0) at miscops.c:554:15 [opt]
frame #13: 0x00000001024d7b2f libcouchbase.cpython-37m-darwin.so`pycbc_Bucket_ping(self=0x0000000105d5ee60, args=<unavailable>, kwargs=0x00000001021b7be0) at miscops.c:472:1 [opt]
frame #14: 0x0000000100123062 Python`PyCFunction_Call + 208
frame #15: 0x00000001001b165a Python`_PyEval_EvalFrameDefault + 7738```
so we are in lcb_wait after calling lcb_ping, above.