Function MemoryStream.peek
Returns a temporary reference to the data that is currently buffered.
const(ubyte)[] peek() @safe;
The returned slice typically has the size leastSize() or 0 if dataAvailableForRead()
returns false. Streams that don't have an internal buffer will always return an empty
slice.
Note that any method invocation on the same stream potentially invalidates the contents of the returned buffer.