in crumb-compiler/src/main/kotlin/com/uber/crumb/internal/model/CrumbMetadata.kt [65:70]
override fun toString(): String {
val result = mutableListOf<String>()
result += """extensionKey=$extensionKey"""
if (producerMetadata.isNotEmpty()) result += """producerMetadata=$producerMetadata"""
return result.joinToString(prefix = "CrumbMetadata{", separator = ", ", postfix = "}")
}