public Builder mergeSource(com.google.cloud.vmmigration.v1.Source value) {
      if (sourceBuilder_ == null) {
        if (((bitField0_ & 0x00000004) != 0)
            && source_ != null
            && source_ != com.google.cloud.vmmigration.v1.Source.getDefaultInstance()) {
          getSourceBuilder().mergeFrom(value);
        } else {
          source_ = value;
        }
      } else {
        sourceBuilder_.mergeFrom(value);
      }
      if (source_ != null) {
        bitField0_ |= 0x00000004;
        onChanged();
      }
      return this;
    }
<pre>
Required. The create request body.
</pre>

<code>
.google.cloud.vmmigration.v1.Source source = 3 [(.google.api.field_behavior) = REQUIRED];
</code>
java-vmmigration/proto-google-cloud-vmmigration-v1/src/main/java/com/google/cloud/vmmigration/v1/CreateSourceRequest.java