Add TTBR information to Cloud documentation (#4307)

* add ttbr information to cloud docs, closes influxdata/DAR#302

* fixed typo, added PR feedback

* Apply suggestions from code review

Co-authored-by: kelseiv <47797004+kelseiv@users.noreply.github.com>

Co-authored-by: kelseiv <47797004+kelseiv@users.noreply.github.com>

content/influxdb/cloud/reference/internals/ttbr.md

@@ -0,0 +1,67 @@
+---
+title: Time To Become Readable
+description: >
+  **Time To Become Readable (TTBR)** is the delay between when you write data to
+  InfluxDB Cloud and when that data becomes queryable.
+  TTBR is variable and is affected by many factors.
+menu:
+  influxdb_cloud_ref:
+    name:  Time To Become Readable
+    parent: InfluxDB Cloud internals
+weight: 102
+influxdb/cloud/tags: [write, query]
+related:
+  - /influxdb/cloud/write-data/
+  - /influxdb/cloud/query-data/
+---
+
+**Time To Become Readable (TTBR)** is the delay between when you write data to
+InfluxDB Cloud and when that data becomes queryable.
+TTBR is variable and is affected by many factors.
+
+- [How write requests work in the InfluxDB Cloud API](#how-write-requests-work-in-the-influxdb-cloud-api)
+- [Flux vs InfluxQL](#flux-vs-influxql)
+- [InfluxDB Cloud TTBRs](#influxdb-cloud-ttbrs)
+
+## How write requests work in the InfluxDB Cloud API
+
+Whenever you send a write request to the `/api/v2/write` endpoint, the following actions occur:
+
+1. API validates the request and queues the write.
+2. If the write is queued, API responds with an HTTP 204 status code.
+3. API handles the write asynchronously and reaches eventual consistency.
+
+_For more information, see [`/api/v2/write` documentation](/influxdb/cloud/api/#operation/PostWrite)._
+
+{{% note %}}
+The returned 204 status code does not mean that the point is queryable;
+it means the write request has been added to the durable write queue
+_(for more information, see
+[Handle write and delete responses](/influxdb/cloud/write-data/troubleshoot/#handle-write-and-delete-responses))_.
+TTBR represents the time it takes for the write request to be queued,
+the write operation to be executed, **and** the data to become queryable.
+
+For more information about status codes returned from the `/api/v1/write` endpoint
+{{% /note %}}
+
+## Flux vs InfluxQL
+
+One of the primary factors that affects TTBR is the query language you use to
+query the newly written data. InfluxQL queries use a metadata cache that stores
+information about fields and series.
+
+**If you write a point with a new field**, the new field will not be queryable
+by InfluxQL until InfluxDB Cloud refreshes the metadata cache, which can take up
+to 15 minutes. Flux does not rely on the metadata cache, so the newly written
+data should be queryable in approximately one second.
+
+**If you write a point with an existing field**, and the field already exists in 
+the metadata cache, both InfluxQL and Flux should be able to query the new data
+in approximately one second.
+
+## InfluxDB Cloud TTBRs
+
+| Write request to   | Flux |      InfluxQL      |
+| :------------- | :--: | :----------------: |
+| Existing field | ≈1s  |        ≈1s         |
+| New field      | ≈1s  | ≈10m to 15m |