diff --git a/third_party/go/opencensus-proto/gen-go/trace/v1/trace_config.pb.go b/third_party/go/opencensus-proto/gen-go/trace/v1/trace_config.pb.go
new file mode 100644
index 0000000..0253877
--- /dev/null
+++ b/third_party/go/opencensus-proto/gen-go/trace/v1/trace_config.pb.go
@@ -0,0 +1,359 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// source: opencensus/proto/trace/v1/trace_config.proto
+
+package v1
+
+import (
+	fmt "fmt"
+	proto "github.com/golang/protobuf/proto"
+	math "math"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
+
+// How spans should be sampled:
+// - Always off
+// - Always on
+// - Always follow the parent Span's decision (off if no parent).
+type ConstantSampler_ConstantDecision int32
+
+const (
+	ConstantSampler_ALWAYS_OFF    ConstantSampler_ConstantDecision = 0
+	ConstantSampler_ALWAYS_ON     ConstantSampler_ConstantDecision = 1
+	ConstantSampler_ALWAYS_PARENT ConstantSampler_ConstantDecision = 2
+)
+
+var ConstantSampler_ConstantDecision_name = map[int32]string{
+	0: "ALWAYS_OFF",
+	1: "ALWAYS_ON",
+	2: "ALWAYS_PARENT",
+}
+
+var ConstantSampler_ConstantDecision_value = map[string]int32{
+	"ALWAYS_OFF":    0,
+	"ALWAYS_ON":     1,
+	"ALWAYS_PARENT": 2,
+}
+
+func (x ConstantSampler_ConstantDecision) String() string {
+	return proto.EnumName(ConstantSampler_ConstantDecision_name, int32(x))
+}
+
+func (ConstantSampler_ConstantDecision) EnumDescriptor() ([]byte, []int) {
+	return fileDescriptor_5359209b41ff50c5, []int{2, 0}
+}
+
+// Global configuration of the trace service. All fields must be specified, or
+// the default (zero) values will be used for each type.
+type TraceConfig struct {
+	// The global default sampler used to make decisions on span sampling.
+	//
+	// Types that are valid to be assigned to Sampler:
+	//	*TraceConfig_ProbabilitySampler
+	//	*TraceConfig_ConstantSampler
+	//	*TraceConfig_RateLimitingSampler
+	Sampler isTraceConfig_Sampler `protobuf_oneof:"sampler"`
+	// The global default max number of attributes per span.
+	MaxNumberOfAttributes int64 `protobuf:"varint,4,opt,name=max_number_of_attributes,json=maxNumberOfAttributes,proto3" json:"max_number_of_attributes,omitempty"`
+	// The global default max number of annotation events per span.
+	MaxNumberOfAnnotations int64 `protobuf:"varint,5,opt,name=max_number_of_annotations,json=maxNumberOfAnnotations,proto3" json:"max_number_of_annotations,omitempty"`
+	// The global default max number of message events per span.
+	MaxNumberOfMessageEvents int64 `protobuf:"varint,6,opt,name=max_number_of_message_events,json=maxNumberOfMessageEvents,proto3" json:"max_number_of_message_events,omitempty"`
+	// The global default max number of link entries per span.
+	MaxNumberOfLinks     int64    `protobuf:"varint,7,opt,name=max_number_of_links,json=maxNumberOfLinks,proto3" json:"max_number_of_links,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *TraceConfig) Reset()         { *m = TraceConfig{} }
+func (m *TraceConfig) String() string { return proto.CompactTextString(m) }
+func (*TraceConfig) ProtoMessage()    {}
+func (*TraceConfig) Descriptor() ([]byte, []int) {
+	return fileDescriptor_5359209b41ff50c5, []int{0}
+}
+
+func (m *TraceConfig) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_TraceConfig.Unmarshal(m, b)
+}
+func (m *TraceConfig) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_TraceConfig.Marshal(b, m, deterministic)
+}
+func (m *TraceConfig) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_TraceConfig.Merge(m, src)
+}
+func (m *TraceConfig) XXX_Size() int {
+	return xxx_messageInfo_TraceConfig.Size(m)
+}
+func (m *TraceConfig) XXX_DiscardUnknown() {
+	xxx_messageInfo_TraceConfig.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_TraceConfig proto.InternalMessageInfo
+
+type isTraceConfig_Sampler interface {
+	isTraceConfig_Sampler()
+}
+
+type TraceConfig_ProbabilitySampler struct {
+	ProbabilitySampler *ProbabilitySampler `protobuf:"bytes,1,opt,name=probability_sampler,json=probabilitySampler,proto3,oneof"`
+}
+
+type TraceConfig_ConstantSampler struct {
+	ConstantSampler *ConstantSampler `protobuf:"bytes,2,opt,name=constant_sampler,json=constantSampler,proto3,oneof"`
+}
+
+type TraceConfig_RateLimitingSampler struct {
+	RateLimitingSampler *RateLimitingSampler `protobuf:"bytes,3,opt,name=rate_limiting_sampler,json=rateLimitingSampler,proto3,oneof"`
+}
+
+func (*TraceConfig_ProbabilitySampler) isTraceConfig_Sampler() {}
+
+func (*TraceConfig_ConstantSampler) isTraceConfig_Sampler() {}
+
+func (*TraceConfig_RateLimitingSampler) isTraceConfig_Sampler() {}
+
+func (m *TraceConfig) GetSampler() isTraceConfig_Sampler {
+	if m != nil {
+		return m.Sampler
+	}
+	return nil
+}
+
+func (m *TraceConfig) GetProbabilitySampler() *ProbabilitySampler {
+	if x, ok := m.GetSampler().(*TraceConfig_ProbabilitySampler); ok {
+		return x.ProbabilitySampler
+	}
+	return nil
+}
+
+func (m *TraceConfig) GetConstantSampler() *ConstantSampler {
+	if x, ok := m.GetSampler().(*TraceConfig_ConstantSampler); ok {
+		return x.ConstantSampler
+	}
+	return nil
+}
+
+func (m *TraceConfig) GetRateLimitingSampler() *RateLimitingSampler {
+	if x, ok := m.GetSampler().(*TraceConfig_RateLimitingSampler); ok {
+		return x.RateLimitingSampler
+	}
+	return nil
+}
+
+func (m *TraceConfig) GetMaxNumberOfAttributes() int64 {
+	if m != nil {
+		return m.MaxNumberOfAttributes
+	}
+	return 0
+}
+
+func (m *TraceConfig) GetMaxNumberOfAnnotations() int64 {
+	if m != nil {
+		return m.MaxNumberOfAnnotations
+	}
+	return 0
+}
+
+func (m *TraceConfig) GetMaxNumberOfMessageEvents() int64 {
+	if m != nil {
+		return m.MaxNumberOfMessageEvents
+	}
+	return 0
+}
+
+func (m *TraceConfig) GetMaxNumberOfLinks() int64 {
+	if m != nil {
+		return m.MaxNumberOfLinks
+	}
+	return 0
+}
+
+// XXX_OneofWrappers is for the internal use of the proto package.
+func (*TraceConfig) XXX_OneofWrappers() []interface{} {
+	return []interface{}{
+		(*TraceConfig_ProbabilitySampler)(nil),
+		(*TraceConfig_ConstantSampler)(nil),
+		(*TraceConfig_RateLimitingSampler)(nil),
+	}
+}
+
+// Sampler that tries to uniformly sample traces with a given probability.
+// The probability of sampling a trace is equal to that of the specified probability.
+type ProbabilitySampler struct {
+	// The desired probability of sampling. Must be within [0.0, 1.0].
+	SamplingProbability  float64  `protobuf:"fixed64,1,opt,name=samplingProbability,proto3" json:"samplingProbability,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *ProbabilitySampler) Reset()         { *m = ProbabilitySampler{} }
+func (m *ProbabilitySampler) String() string { return proto.CompactTextString(m) }
+func (*ProbabilitySampler) ProtoMessage()    {}
+func (*ProbabilitySampler) Descriptor() ([]byte, []int) {
+	return fileDescriptor_5359209b41ff50c5, []int{1}
+}
+
+func (m *ProbabilitySampler) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_ProbabilitySampler.Unmarshal(m, b)
+}
+func (m *ProbabilitySampler) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_ProbabilitySampler.Marshal(b, m, deterministic)
+}
+func (m *ProbabilitySampler) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_ProbabilitySampler.Merge(m, src)
+}
+func (m *ProbabilitySampler) XXX_Size() int {
+	return xxx_messageInfo_ProbabilitySampler.Size(m)
+}
+func (m *ProbabilitySampler) XXX_DiscardUnknown() {
+	xxx_messageInfo_ProbabilitySampler.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_ProbabilitySampler proto.InternalMessageInfo
+
+func (m *ProbabilitySampler) GetSamplingProbability() float64 {
+	if m != nil {
+		return m.SamplingProbability
+	}
+	return 0
+}
+
+// Sampler that always makes a constant decision on span sampling.
+type ConstantSampler struct {
+	Decision             ConstantSampler_ConstantDecision `protobuf:"varint,1,opt,name=decision,proto3,enum=opencensus.proto.trace.v1.ConstantSampler_ConstantDecision" json:"decision,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}                         `json:"-"`
+	XXX_unrecognized     []byte                           `json:"-"`
+	XXX_sizecache        int32                            `json:"-"`
+}
+
+func (m *ConstantSampler) Reset()         { *m = ConstantSampler{} }
+func (m *ConstantSampler) String() string { return proto.CompactTextString(m) }
+func (*ConstantSampler) ProtoMessage()    {}
+func (*ConstantSampler) Descriptor() ([]byte, []int) {
+	return fileDescriptor_5359209b41ff50c5, []int{2}
+}
+
+func (m *ConstantSampler) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_ConstantSampler.Unmarshal(m, b)
+}
+func (m *ConstantSampler) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_ConstantSampler.Marshal(b, m, deterministic)
+}
+func (m *ConstantSampler) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_ConstantSampler.Merge(m, src)
+}
+func (m *ConstantSampler) XXX_Size() int {
+	return xxx_messageInfo_ConstantSampler.Size(m)
+}
+func (m *ConstantSampler) XXX_DiscardUnknown() {
+	xxx_messageInfo_ConstantSampler.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_ConstantSampler proto.InternalMessageInfo
+
+func (m *ConstantSampler) GetDecision() ConstantSampler_ConstantDecision {
+	if m != nil {
+		return m.Decision
+	}
+	return ConstantSampler_ALWAYS_OFF
+}
+
+// Sampler that tries to sample with a rate per time window.
+type RateLimitingSampler struct {
+	// Rate per second.
+	Qps                  int64    `protobuf:"varint,1,opt,name=qps,proto3" json:"qps,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *RateLimitingSampler) Reset()         { *m = RateLimitingSampler{} }
+func (m *RateLimitingSampler) String() string { return proto.CompactTextString(m) }
+func (*RateLimitingSampler) ProtoMessage()    {}
+func (*RateLimitingSampler) Descriptor() ([]byte, []int) {
+	return fileDescriptor_5359209b41ff50c5, []int{3}
+}
+
+func (m *RateLimitingSampler) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_RateLimitingSampler.Unmarshal(m, b)
+}
+func (m *RateLimitingSampler) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_RateLimitingSampler.Marshal(b, m, deterministic)
+}
+func (m *RateLimitingSampler) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_RateLimitingSampler.Merge(m, src)
+}
+func (m *RateLimitingSampler) XXX_Size() int {
+	return xxx_messageInfo_RateLimitingSampler.Size(m)
+}
+func (m *RateLimitingSampler) XXX_DiscardUnknown() {
+	xxx_messageInfo_RateLimitingSampler.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_RateLimitingSampler proto.InternalMessageInfo
+
+func (m *RateLimitingSampler) GetQps() int64 {
+	if m != nil {
+		return m.Qps
+	}
+	return 0
+}
+
+func init() {
+	proto.RegisterEnum("opencensus.proto.trace.v1.ConstantSampler_ConstantDecision", ConstantSampler_ConstantDecision_name, ConstantSampler_ConstantDecision_value)
+	proto.RegisterType((*TraceConfig)(nil), "opencensus.proto.trace.v1.TraceConfig")
+	proto.RegisterType((*ProbabilitySampler)(nil), "opencensus.proto.trace.v1.ProbabilitySampler")
+	proto.RegisterType((*ConstantSampler)(nil), "opencensus.proto.trace.v1.ConstantSampler")
+	proto.RegisterType((*RateLimitingSampler)(nil), "opencensus.proto.trace.v1.RateLimitingSampler")
+}
+
+func init() {
+	proto.RegisterFile("opencensus/proto/trace/v1/trace_config.proto", fileDescriptor_5359209b41ff50c5)
+}
+
+var fileDescriptor_5359209b41ff50c5 = []byte{
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