Lambda in VPC without cold start penalty (Hyperplane ENIs).

In Simple Words: AWS uses Hyperplane (shared network virtualization technology). Rather than creating a new Elastic Network Interface (ENI) for every single Lambda instance, Lambdas attach to pre-provisioned shared Hyperplane ENIs, eliminating the multi-second VPC cold start penalty.

# Attaching Lambda to VPC Subnets and Security Groups:
resource "aws_lambda_function" "vpc_lambda" {
  function_name = "VpcService"
  vpc_config {
    subnet_ids         = aws_subnet.private[*].id
    security_group_ids = [aws_security_group.lambda_sg.id]
  }
}