Support Sagemaker async endpoint deployment.

[yinsong1986]

Description

Some one reported error when deploying models on LMI Sagemaker containers using Sagemaker async endpoint. Please refer to vllm-project/vllm#2912

Expected Behavior

Error Message

2024-11-16T23:22:06.943:[sagemaker logs] [xxxxxxxxxxxxxxxxxxxxxx] The response from container primary did not specify the required Content-Length header

How to Reproduce?

(If you developed your own code, please provide a short script that reproduces the error. For existing examples, please provide link.)

Steps to reproduce

[(Paste the commands you ran that produced the error.)

(vllm-project/vllm#2912)

What have you tried to solve it?