remove zero duration span and dead code (#1730)

Author: breedx-splk

demo-app/src/main/java/io/opentelemetry/android/demo/DemoViewModel.kt

@@ -13,7 +13,6 @@ import kotlinx.coroutines.launch
 
 class DemoViewModel : ViewModel() {
     val sessionIdState = MutableStateFlow("? unknown ?")
-    private val tracer = OtelDemoApplication.tracer("otel.demo")!!
 
     init {
         viewModelScope.launch {
@@ -27,12 +26,4 @@ class DemoViewModel : ViewModel() {
     private fun updateSession() {
         // TODO
     }
-
-    private fun sendTrace(
-        type: String,
-        value: Float,
-    ) {
-        // A metric should be a better fit, but for now we're using spans.
-        tracer.spanBuilder(type).setAttribute("value", value.toDouble()).startSpan().end()
-    }
 }

demo-app/src/main/java/io/opentelemetry/android/demo/MainOtelButton.kt

@@ -21,7 +21,6 @@ import androidx.compose.ui.semantics.onClick
 import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.unit.dp
 import io.opentelemetry.api.metrics.LongCounter
-import io.opentelemetry.api.trace.SpanKind
 
 @Composable
 fun MainOtelButton(icon: Painter,
@@ -51,14 +50,5 @@ fun generateClickEvent(counter: LongCounter?) {
     val scope = "otel.demo.app"
     OtelDemoApplication.eventBuilder(scope, "logo.clicked")
         .emit()
-    // For now, we also emit a span, so that we can see something in a UI
-    val tracer = OtelDemoApplication.tracer(scope)
-    // And we also increment a counter, to test metrics
     counter?.add(1)
-    val span =
-        tracer
-            ?.spanBuilder("logo.clicked")
-            ?.setSpanKind(SpanKind.INTERNAL)
-            ?.startSpan()
-    span?.end()
 }