http-client-branch: remove redundant null check

http-client-branch: HttpHeadersImpl use more efficient entrySet

http-client-branch: use UTF-8 for all convertions to String

http-client-branch: immutable data Flow

http-client-branch: add tests with an HTTP/2 server for custom basic and digest authentication

http-client-branch: merge

http-client-branch: possible null dereference in Exchange

http-client-branch: remove redundant null check in Http1Request

http-client-branch: (WebSocket) merge (2)

http-client-branch: (WebSocket) merge

http-client-branch: (WebSocket) cleanup

http-client-branch: inconsistent synchronization in ConnectionPool

http-client-branch: inconsistent synchronization of PushGroup

http-client-branch: incorrect protected field in final class

http-client-branch: fix serializable fields in internal ALPNException

http-client-branch: fix mutable byte[] references

http-client-branch: (WebSocket) example-test

http-client-branch: (WebSocket) test

http-client-branch: long lines in ServerPushWithDiffTypes

http-client-branch: (WebSocket) tiny spec simplification + test

http-client-branch: honor legacy jdk.http.auth.* property when handling proxy-authorization

http-client-branch: update debugging output in SplitResponse

http-client-branch: (WebSocket) test rename

http-client-branch: (WebSocket) tests

http-client-branch: expand FlowAdapterSubscriberTest with mapping using convenience handlers

http-client-branch: only add h2 ALPN if TLSv1.2 or greater

http-client-branch: (WebSocket) A test for onClose & IllegalStateException

http-client-branch: (WebSocket) consistent method names in test