Add primitive versions of setMetric to DDSpanContext

dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java

@@ -751,6 +751,30 @@ public void setMetric(final CharSequence key, final Number value) {
     }
   }
 
+  public void setMetric(final CharSequence key, final int value) {
+    synchronized (unsafeTags) {
+      unsafeTags.set(key.toString(), value);
+    }
+  }
+
+  public void setMetric(final CharSequence key, final long value) {
+    synchronized (unsafeTags) {
+      unsafeTags.set(key.toString(), value);
+    }
+  }
+
+  public void setMetric(final CharSequence key, final float value) {
+    synchronized (unsafeTags) {
+      unsafeTags.set(key.toString(), value);
+    }
+  }
+
+  public void setMetric(final CharSequence key, final double value) {
+    synchronized (unsafeTags) {
+      unsafeTags.set(key.toString(), value);
+    }
+  }
+
   /**
    * Sets a tag to the span. Tags are not propagated to the children.
    *

dd-trace-core/src/test/java/datadog/trace/core/SpanTest.java

@@ -0,0 +1,50 @@
+package datadog.trace.core;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
+import org.junit.jupiter.api.Test;
+
+public class SpanTest {
+  static final CoreTracer TRACER = CoreTracer.builder().build();
+
+  @Test
+  public void setMetric_int() {
+    int expected = 2;
+
+    AgentSpan span = TRACER.startSpan("foo", "foo");
+    span.setMetric("int", expected);
+
+    assertEquals(Integer.valueOf(expected), span.getTag("int"));
+  }
+
+  @Test
+  public void setMetric_long() {
+    long expected = 20L;
+
+    AgentSpan span = TRACER.startSpan("foo", "foo");
+    span.setMetric("long", expected);
+
+    assertEquals(Long.valueOf(expected), span.getTag("long"));
+  }
+
+  @Test
+  public void setMetric_float() {
+    float expected = 2.718F;
+
+    AgentSpan span = TRACER.startSpan("foo", "foo");
+    span.setMetric("float", expected);
+
+    assertEquals(Float.valueOf(expected), span.getTag("float"));
+  }
+
+  @Test
+  public void setMetric_double() {
+    double expected = 3.1415D;
+
+    AgentSpan span = TRACER.startSpan("foo", "foo");
+    span.setMetric("double", expected);
+
+    assertEquals(Double.valueOf(expected), span.getTag("double"));
+  }
+}