AlignedBytes.swift

public extension ArraySlice {
    private func array() -> [Element] {
        return Array(self)
    }

    func withAlignedBytes<R>(_ body: (UnsafeRawBufferPointer) throws -> R) rethrows -> R {
        if startIndex == 0 || startIndex % MemoryLayout<R>.alignment == 0 {
            return try self.withUnsafeBytes(body)
        } else {
            return try self.array().withUnsafeBytes(body)
        }
    }
}