In essence, they are `[]byte` -> `[]byte, error` functions.

It is not possible to return *both* an error and a response.

Handlers are registered on the manager using `(*Manager).RegisterSingleHandler(id HandlerID, h SingleHandlerFn, subroute ...string)`.

The server handler function has this signature: `type SingleHandlerFn func(payload []byte) ([]byte, *RemoteErr)`.

Sample handler:
```go

        "java.lang.String" to "String",
        "java.lang.Character" to "Char",
        "char" to "Char",
        "java.lang.Boolean" to "Boolean",
        "boolean" to "Boolean",
        "java.lang.Byte" to "Byte",
        "byte" to "Byte",
        "java.lang.Short" to "Short",
        "short" to "Short",
        "java.lang.Integer" to "Int",
        "int" to "Int",
        "java.lang.Long" to "Long",
        "long" to "Long",

        )
      }
    }

    if (isControlFrame && frameLength > PAYLOAD_BYTE_MAX) {
      throw ProtocolException("Control frame must be less than ${PAYLOAD_BYTE_MAX}B.")
    }

    if (isMasked) {
      // Read the masking key as bytes so that they can be used directly for unmasking.
      source.readFully(maskKey!!)
    }
  }

  @Throws(IOException::class)

 * prefix are called a 'section'. There are 128 code points per section.
 *
 * Ranges Data (32,612 bytes)
 * ==========================
 *
 * Each entry is 4 bytes, and represents a _range_ of code points that all share a common 14-bit
 * prefix. Entries are sorted by their complete code points.
 *
 * The 4 bytes are named b0, b1, b2 and b3. We also define these supplemental values:
 *
 *  * **b2a**: b2 + 0x80

 * limitations under the License.
 */
package okhttp3.tls.internal.der

/**
 * The first two bytes of each value is a header that includes its tag (field ID) and length.
 */
internal data class DerHeader(
  /**
   * Namespace of the tag.
   *
   * This value is encoded in bits 7 and 8 of the first byte of each value.
   *
   * ```
   * 0b00xxxxxx Universal
   * 0b01xxxxxx Application

   * not terminated.
   *
   * Use this method to create a degenerate Okio Buffer where each byte is in a separate segment of
   * the internal list.
   */
  @JvmStatic
  fun fragmentBuffer(buffer: Buffer): Buffer {
    // Write each byte into a new buffer, then clone it so that the segments are shared.
    // Shared segments cannot be compacted so we'll get a long chain of short segments.

  @Test fun validateCompactTableInvariants() {
    // Less than 16,834 bytes, because we binary search on a 14-bit index.
    assertThat(compactTable.sections.length).isLessThan(1 shl 14)

    // Less than 65,536 bytes, because we binary search on a 14-bit index with a stride of 4 bytes.
    assertThat(compactTable.ranges.length).isLessThan((1 shl 14) * 4)

            )
          } else if (gzippedLength != null) {
            logger.log("--> END ${request.method} (${buffer.size}-byte, $gzippedLength-gzipped-byte body)")
          } else {
            logger.log(buffer.readString(charset))
            logger.log("--> END ${request.method} (${requestBody.contentLength()}-byte body)")
          }
        }
      }

    api(platform("gradlebuild:build-platform"))
    implementation("gradlebuild:gradle-plugin")

    implementation(localGroovy())
    testImplementation("org.spockframework:spock-core")
    testImplementation("net.bytebuddy:byte-buddy")
    testImplementation("org.objenesis:objenesis")
}

tasks.withType<GroovyCompile>().configureEach {
    groovyOptions.apply {
        encoding = "utf-8"

      if (type == TYPE_A || type == TYPE_AAAA) {
        val bytes = ByteArray(length)
        buf.read(bytes)
        result.add(InetAddress.getByAddress(bytes))
      } else {
        buf.skip(length.toLong())
      }
    }

    return result
  }

  @Throws(EOFException::class)
  private fun skipName(source: Buffer) {
    // 0 - 63 bytes
    var length = source.readByte().toInt()