MetricExpansion

  @usableFromInline
  func _read(pathView: PathView) throws(IOError) -> [UInt8] {
      var file = try File(pathView)
      var bytes: [UInt8] = []
      try file.readToEnd(into: &bytes)
      return bytes
  }
  
  @inlinable
  public func read<Path>(path: borrowing Path) throws(IOError) -> [UInt8] where Path: PathViewable, Path: ~Copyable {
      try _read(pathView: path.view())
  }
  
  // Definitions...
  
  public enum IOError: Error {}
  
  public protocol PathViewable: ~Copyable {
      func view() -> PathView
  }
  
  public struct PathView: ~Escapable {}
  
  public struct File: ~Copyable {
      public init(_ pathView: borrowing PathView) throws(IOError) {
          fatalError("unimplemented")
      }
  
      public mutating func readToEnd(into buffer: inout [UInt8]) throws(IOError) {
          fatalError("unimplemented")
      }
  }