CHANGES:

• API breaking change: remove usage of Cstruct.t inside of TLS, use bytes and string instead (#497 by @art-w, @hannesm, @dinosaure, @reynir) Performance is up to 3x improved (bandwidth), 2x improvement for handshake/s on an Intel Core(TM) i7-5600U CPU @ 2.60GHz
• FEATURE: add tls-miou-unix package, which adds miou support for TLS (#494 #503 @dinosaure)
• FEATURE: tls-lwt and tls-async: allow TLS over an existing connection Tls_lwt.client_of_channels : Tls.Config.client -> ?host:[host] Domain_name.t -> Lwt_io.input_channel * Lwt_io.output_channel -> t Lwt.tandTls_lwt.server_of_channels : Tls.Config.server -> Lwt_io.input_channel * Lwt_io.output_channel -> t Lwt.t` (#499 @art-w @MisterDA)
• API breaking changes: revise errors - reduce the polymorphic variant in size, align it with RFC specified errors, be in parts more precise about errors, in other parts skip data (#505, @hannesm - fixes #491) NB: if you relied on a specific error constructor, please open an issue
• Remove unused constructors from Packet.{alert_type, compression_methods, client_certificate_type, extension_type} (#505, @hannesm) NB: if you relied on specific constructors, please open an issue
• API breaking change: Tls.Config.{server,client} now return a result type instead of raising an exception (#502, @hannesm, fixes #411)
• FEATURE: add bench/speed.exe, a benchmark for bandwidth (for different ciphersuites) and handshakes (different key exchanges and private keys) (#500 @hannesm @dinosaure @reynir)
• BUGFIX: tests/feedback.exe update with TLS 1.3 semantics, run as test (#501, @hannesm - reported by @dinosaure)