Concurrency helpers

Various concurrency related tools, including Lock and async stream additions etc.

To add to your project:

dependencies: [
    .package(url: "https://github.com/ordo-one/package-concurrency-helpers", .upToNextMajor(from: "0.0.1")),
]

and then add the dependency to your target, e.g.:

.executableTarget(
  name: "MyExecutableTarget",
  dependencies: [
  .product(name: "SwiftConcurrencyHelpers", package: "package-concurrency-helpers")
]),