[exporter/prometheusremotewrite] Hash labels using xxhash for performance

.chloggen/arve_xxhash.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: prometheusremotewrite
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Optimize the prometheusremotewrite.FromMetrics function, based around more performant metric identifier hashing.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [31385]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]

pkg/translator/prometheusremotewrite/go.mod

@@ -3,6 +3,7 @@ module github.com/open-telemetry/opentelemetry-collector-contrib/pkg/translator/
 go 1.21
 
 require (
+	github.com/cespare/xxhash/v2 v2.3.0
 	github.com/open-telemetry/opentelemetry-collector-contrib/internal/coreinternal v0.98.0
 	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/translator/prometheus v0.98.0
 	github.com/prometheus/common v0.52.2