* Add CopyrightHeader support for sbt-boilerplate plugin.
* Add CopyrightHeader support for `*.proto` files.
* Add regex match for both `–` and `-` for CopyrightHeader.
* Add CopyrightHeader support for sbt build files.
* Update copyright from 2018 to 2019.
* #22506 Mark materializer extension as @InternalApi
* #22506 Added missing annotations on internal apis in the fusing package
* #22506 Missing annotations in io package
* #22506 Add internal api annotations in impl package
* #22563 more hiding of the classes in the impl package
* #22563 Formatting fixes
* #22506 Fix private access in stream tcl tests