Was Appellant's waiver of his Sixth Amendment right to trial, pursuant to a plea agreement, freely and voluntarily made or the product of coercion — thus invalid?

QUESTION PRESENTED Was Appellant’s waiver of his Sixth Amendment right to trial, pursuant to a plea agreement, freely and voluntarily made or the product of coercion — thus invalid — where Appellant pled guilty to the charges after his trial counsel threatened Appellant that counsel would withdraw from the case and abandon Appellant and the case if Appellant did not accept the Commonwealth’s plea offer?