• Deprecated expect_close attribute in Mojo::Content.
  
• Removed deprecated delay helper from Mojolicious::Plugin::DefaultHelpers.
  
• Changed error message for destroyed transactions from "Connection already closed" to
  "Transaction already destroyed".
  
• Fixed a race condition in Mojo::UserAgent where closing connections could sometimes end up being reused.
  
• Fixed an RFC 7230 compliance problem where HTTP/1.1 responses were sometimes incomplete.