kraken: add crash-handling around `Pair()` init

Since it can otherwise be difficult to debug due to nursery cancellation
(we need that taskman yo!).

piker/brokers/kraken/api.py

@@ -34,6 +34,7 @@ import urllib.parse
 import hashlib
 import hmac
 import base64
+import tractor
 import trio
 
 from piker import config
@@ -372,8 +373,7 @@ class Client:
         #     1658347714, 'status': 'Success'}]}
 
         if xfers:
-            import tractor
-            await tractor.pp()
+            await tractor.pause()
 
         trans: dict[str, Transaction] = {}
         for entry in xfers:
@@ -501,7 +501,8 @@ class Client:
             for xkey, data in resp['result'].items():
 
                 # NOTE: always cache in pairs tables for faster lookup
-                pair = Pair(xname=xkey, **data)
+                with tractor.devx.maybe_open_crash_handler(): # as bxerr:
+                    pair = Pair(xname=xkey, **data)
 
                 # register the above `Pair` structs for all
                 # key-sets/monikers: a set of 4 (frickin) tables