very-high latency updates through thrift proxy server

[Jeff Turner]

any ideas why mutations via thrift proxy server would take 120 to 150 
seconds to show up in a scan?

accumulo 1.9.3
the mutations have all been submitted through thrift (from python), the 
writer has been closed, and the writing process has exited.

95% of the time, the latency is between 120.1 and 120.5 seconds. 
occasionally the latency is 150 seconds.

there don't appear to be many configuration options for the proxy 
server.  and other people i have talked to said that they see their 
updates through thrift proxy immediately.

updates via java/jython have millisecond latency.  (for a while i had 
been trying to blame tservers or the main server (maybe some delay in 
processing compactions, ...).  i don't think that's the issue)