 
   /// 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, which must have remaining capacity.
  mutating func addWithExistingCapacity(element: Element) {
    _sanityCheck(remainingCapacity > 0,
      "_UnsafePartiallyInitializedContiguousArrayBuffer has no more capacity")

  }

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