public Optional<EventStreamInfo> getInputInfo(ToShapeId operationShape) {
        return Optional.ofNullable(inputInfo.get(operationShape.toShapeId()));
    }
Get event stream information for the input of an operation.

<p>No result is returned if the provided operation shape does not
exist, if the targeted shape is not an operation, if the operation
does not contain an input structure or if the input structure does
not contain an input event stream.

@param operationShape Operation or shape ID to retrieve information for.
@return Returns the optionally found input event stream information.
smithy-model/src/main/java/software/amazon/smithy/model/knowledge/EventStreamIndex.java