What is the current state of the law on the crime of involuntary manslaughter?

Even if we were to ignore the weight of this precedent and conclude that the trial court erred in not instructing the jury on the crime of involuntary manslaughter, that error was both harmless beyond a reasonable doubt (Chapman v. California (1967) 386 U.S. 18, 24), and not reasonably probable to have caused a more favorable result (People v. Watson (1956) 46 Cal.2d 818, 836) for the same reasons outlined abovenamely, the evidence of defendant's implied malice was overwhelming.