protocol := thrift.NewBinaryProtocol(transport) err := protocol.WriteFieldBegin("foo", thrift.STRING, 1) if err != nil { // handle error } _, err = protocol.WriteString("bar") if err != nil { // handle error } err = protocol.WriteFieldEnd() if err != nil { // handle error }In this example, a Thrift BinaryProtocol is used to write a field named "foo" with a string value of "bar". The WriteFieldBegin function is first called to indicate the beginning of the field. Then, the WriteString function is called to write the value of the field. Finally, the WriteFieldEnd function is called to mark the end of the field. The package library for this function is "git-wip-us.apache.org/repo/asf/thrift.git/lib/go/thrift".