def download_fileobj(Fileobj=None, Bucket=None, Key=None, ExtraArgs=None,
    Callback=None, Config=None):
    """
    Download an object from S3 to a file-like object.
    The file-like object must be in binary mode.
    This is a managed transfer which will perform a multipart download in
    multiple threads if necessary.
    :
    
    :example: import boto3
    s3 = boto3.client('s3')
    
    with open('filename', 'wb') as data:
        s3.download_fileobj('mybucket', 'mykey', data)
    
    
    :type Fileobj: a file-like object
    :param Fileobj: A file-like object to download into. At a minimum, it must
            implement the write method and must accept bytes.

    :type Bucket: str
    :param Bucket: The name of the bucket to download from.

    :type Key: str
    :param Key: The name of the key to download from.

    :type ExtraArgs: dict
    :param ExtraArgs: Extra arguments that may be passed to the
            client operation.

    :type Callback: method
    :param Callback: A method which takes a number of bytes transferred to
            be periodically called during the download.

    :type Config: boto3.s3.transfer.TransferConfig
    :param Config: The transfer configuration to be used when performing the
            download.

    """
    pass
