document remote write queue parameters (#4126)

docs/configuration/configuration.md

@@ -1193,6 +1193,24 @@ tls_config:
 
 # Optional proxy URL.
 [ proxy_url: <string> ]
+
+# Configures the queue used to write to remote storage.
+queue_config:
+  # Number of samples to buffer per shard before we start dropping them.
+  [ capacity: <int> | default = 100000 ]
+  # Maximum number of shards, i.e. amount of concurrency.
+  [ max_shards: <int> | default = 1000 ]
+  # Maximum number of samples per send.
+  [ max_samples_per_send: <int> | default = 100]
+  # Maximum time a sample will wait in buffer.
+  [ batch_send_deadline: <duration> | default = 5s ]
+  # Maximum number of times to retry a batch on recoverable errors.
+  [ max_retries: <int> | default = 10 ]
+  # Initial retry delay. Gets doubled for every retry.
+  [ min_backoff: <duration> | default = 30ms ]
+  # Maximum retry delay.
+  [ max_backoff: <duration> | default = 100ms ]
+
 ```
 
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