class_docstr: Abstract class for KVStore defining APIs needed for ray serve
  use cases, currently (8/6/2021) controller state checkpointing.
docstr: Put object into kv store, bytes only.
  
  Args:
      key: Key for object to be stored.
      val: Byte value of object.
docstr_tok: ["Put","object","into","kv","store",",","bytes","only",".","Args",":","key",":","Key","for","object","to","be","stored",".","val",":","Byte","value","of","object","."]
code: def put(self, key: str, val: bytes) -> bool:
      """Put object into kv store, bytes only.
  
      Args:
          key: Key for object to be stored.
          val: Byte value of object.
      """
      raise NotImplementedError("put() has to be implemented")
  
file_path: ray/python/ray/serve/_private/storage/kv_store_base.py
imports: import abc
  from abc import abstractmethod
  from typing import Optional
  from ray.util.annotations import DeveloperAPI
label_desc: Use image node_id 2 for calling the KVStoreBase obj's underlying member method code with example usage: obj.put(key, val) without return types