A company's application has an AWS Lambda function that processes messages from loT devices. The company wants to monitor the Lambda function to ensure that the Lambda function is meeting its required service level agreement (SLA).

A developer must implement a solution to determine the application's throughput in near real time. The throughput must be based on the number of messages that the Lambda function receives and processesin a given time period. The Lambda function performs initialization and post-processing steps that must not factor into the throughput measurement.

What should the developer do to meet these requirements?