static boolean primitiveContent(JsonToken current, JsonToken next) {
        if (current.isScalarValue()) return true;
        if (current == JsonToken.START_ARRAY) {
            if (next == JsonToken.END_ARRAY) return false;
            if (next.isScalarValue()) return true;
        }
        return false;
    }
Reads the tensor format defined at
See <a href="https://docs.vespa.ai/en/reference/document-json-format.html">https://docs.vespa.ai/en/reference/document-json-format.html</a>

@author geirst
@author bratseth
document/src/main/java/com/yahoo/document/json/readers/TensorReader.java