float Montage_PlayWithBlendIn ( [UAnimMontage](API\Runtime\Engine\Animation\UAnimMontage) * MontageToPlay, const [FAlphaBlendArgs](API\Runtime\Engine\FAlphaBlendArgs) & BlendIn, float InPlayRate, EMontagePlayReturnType ReturnValueType, float InTimeToStartMontageAt, bool bStopAllMontages )