Inserts metadata into the active stream of the specified channel. At most 5 requests per second per channel are allowed, each with a maximum 1 KB payload. (If 5 TPS is not sufficient for your needs, we recommend batching your data into a single PutMetadata call.) At most 155 requests per second per account are allowed. Also see <a href="https://docs.aws.amazon.com/ivs/latest/userguide/metadata.html">Embedding Metadata within a Video Stream</a> in the <i>Amazon IVS User Guide</i>.