 
   /// Initialize the buffer with an initial size of `initialCapacity`
   /// elements.
+  @inline(__always) // For performance reasons.
   init(initialCapacity: Int) {
     if initialCapacity == 0 {
       result = _ContiguousArrayBuffer()

  }

  /// Add an element to the buffer, reallocating if necessary.
  mutating func add(element: Element) {
    if remainingCapacity == 0 {
      // Reallocate.

  ///
  /// Returns the fully-initialized buffer. `self` is reset to contain an
  /// empty buffer and cannot be used afterward.
  @inline(__always) // For performance reasons.
  mutating func finishWithOriginalCount() -> _ContiguousArrayBuffer<Element> {
    _sanityCheck(remainingCapacity == result.capacity - result.count,
      "_UnsafePartiallyInitializedContiguousArrayBuffer has incorrect count")
