diff --git a/src/collector.rs b/src/collector.rs
index 66270c4..f5c95a0 100644
--- a/src/collector.rs
+++ b/src/collector.rs
@@ -37,5 +37,5 @@ use crate::encoding::DescriptorEncoder;
 /// ```
 pub trait Collector: std::fmt::Debug + Send + Sync + 'static {
     /// Once the [`Collector`] is registered, this method is called on each scrape.
-    fn encode(&self, encoder: DescriptorEncoder) -> Result<(), std::fmt::Error>;
+    fn encode(&self, encoder: &mut DescriptorEncoder) -> Result<(), std::fmt::Error>;
 }
diff --git a/src/encoding/text.rs b/src/encoding/text.rs
index ca44aa9..aaac9cc 100644
--- a/src/encoding/text.rs
+++ b/src/encoding/text.rs
@@ -1077,7 +1077,7 @@ mod tests {
         impl crate::collector::Collector for Collector {
             fn encode(
                 &self,
-                mut encoder: crate::encoding::DescriptorEncoder,
+                encoder: &mut crate::encoding::DescriptorEncoder,
             ) -> Result<(), std::fmt::Error> {
                 let counter = crate::metrics::counter::ConstCounter::new(42u64);
                 let mut metric_encoder = encoder.encode_descriptor(
diff --git a/src/registry.rs b/src/registry.rs
index 77653e2..2b1a83b 100644
--- a/src/registry.rs
+++ b/src/registry.rs
@@ -300,9 +300,9 @@ impl Registry {
         }
 
         for collector in self.collectors.iter() {
-            let descriptor_encoder =
+            let mut descriptor_encoder =
                 encoder.with_prefix_and_labels(self.prefix.as_ref(), &self.labels);
-            collector.encode(descriptor_encoder)?;
+            collector.encode(&mut descriptor_encoder)?;
         }
 
         for registry in self.sub_registries.iter() {