Obtains connection state on accept for DTLS connections

[jaredwolff]

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This allows you to access the inner connection state of the DTLS connection. Having the connection identity is helpful in server code.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 11.11111% with 24 lines in your changes are missing coverage. Please review.

Project coverage is 61.65%. Comparing base (a97d49e) to head (ee9b09d).

Files	Patch %	Lines
ice/src/agent/agent_test.rs	0.00%	2 Missing :warning:
ice/src/agent/agent_transport.rs	0.00%	2 Missing :warning:
ice/src/agent/agent_vnet_test.rs	0.00%	2 Missing :warning:
ice/src/udp_mux/udp_mux_conn.rs	0.00%	2 Missing :warning:
.../association_internal/association_internal_test.rs	0.00%	2 Missing :warning:
util/src/conn/conn_bridge.rs	0.00%	2 Missing :warning:
util/src/conn/conn_disconnected_packet.rs	0.00%	2 Missing :warning:
util/src/conn/conn_pipe.rs	0.00%	2 Missing :warning:
util/src/conn/conn_udp.rs	0.00%	2 Missing :warning:
util/src/conn/conn_udp_listener.rs	0.00%	2 Missing :warning:
... and 2 more

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #465      +/-   ##
==========================================
- Coverage   61.71%   61.65%   -0.06%     
==========================================
  Files         529      529              
  Lines       48828    48852      +24     
  Branches    12250    12260      +10     
==========================================
- Hits        30134    30121      -13     
- Misses       9532     9572      +40     
+ Partials     9162     9159       -3     

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[jaredwolff]

Missed this. Thanks @rainliu! I was having a bunch of trouble understanding/getting the downcast to work. Let me try it and then update this PR if it works out.