   func _bufferedScalar(bitCount: UInt8) -> Encoding.EncodedScalar
 }
 
-extension _UTFDecoder where Encoding.EncodedScalar == _UIntBuffer<UInt32, Encoding.CodeUnit> {
+extension _UTFDecoder
+where Encoding.EncodedScalar == _UIntBuffer<UInt32, Encoding.CodeUnit> {
   public mutating func parseScalar<I : IteratorProtocol>(
     from input: inout I
   ) -> Unicode.ParseResult<Encoding.EncodedScalar>

  }
}

extension
 Unicode.UTF8.ForwardDecoder : _UTFDecoder {
  public typealias Encoding = Unicode.UTF8
  
  public // @testable

      }
      // Non-ASCII, proceed to buffering mode.
      buffer.append(codeUnit)
    } else if Encoding._isScalar(
      Encoding.CodeUnit(extendingOrTruncating: buffer._storage)
    ) {
      // ASCII in buffer.  We don't refill the buffer so we can return
      // to bufferless mode once we've exhausted it.
      let codeUnit = Encoding.CodeUnit(extendingOrTruncating: buffer._storage)
