Assertion:
"assertion s/strategy_shard.cpp:175"

Basic premise:

• Testing multi-threaded inserts into a single collection
• Running 50 insert threads against a single mongoS
• Testing runs fine for several hundred thousand inserts
• Testing then start throwing this exception

Shard key: a simple _id.

Exception:

• does not occur with { java : 2.5.3, server : 1.6.5 }
• does not occur with { java : 2.3, server : 1.8.1 }
• does not occur with { java : 2.3, server : 1.6.5 }
• is returned from a "GetLastError" call. (see attached for code)
• seems to occur at about 11 or 12 chunks (9:1:1)

(note: this may be a server bug, but given that older java drivers do not have the error, it should start here)