If DC is enabled, wait until the DC state is complete before returning control back to the application

[WesleyRosenblum]

Problem:

Currently, if an application specifies a dc provider, the client and server still return control back to the application before the dc state has been completed. This may result in the application dropping the client or server connection prematurely, if they don't intentionally wait for the completion of the dc state.

Solution:

If dc has been negotiated, do not return control back to the application until the dc::State is Complete

• Does this change what s2n-quic sends over the wire? No
• Does this change any public APIs? Changes the behavior of the accept()/connect() APIs

Requirements / Acceptance Criteria:

• **Testing:**The dc Integration tests should be updated